Fix zeroize dependency in a more future-proof fashion (#321)

* cargo: make zeroize dependency more generous

* Release v0.6.2

* Updating MSRV and changelog

---------

Co-authored-by: Kevin Lewi <[email protected]>

.github/workflows/main.yml

@@ -16,8 +16,8 @@ jobs:
           - u64_backend
           - u32_backend
         toolchain:
-          - stable
-          - 1.41.0
+          - nightly
+          - 1.56.0
     name: test
     steps:
       - name: Checkout sources
@@ -72,6 +72,20 @@ jobs:
       - uses: hecrj/setup-rust-action@v1
       - run: cargo test --verbose --features slow-hash --no-default-features --features ${{ matrix.backend_feature }}
 
+  serde-test:
+    name: Test on ${{ matrix.target }} with serde support
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        backend_feature:
+          - u64_backend
+          - u32_backend
+    steps:
+      - uses: actions/checkout@v2
+      - uses: hecrj/setup-rust-action@v1
+      - run: cargo test --verbose --features serialize --no-default-features --features ${{ matrix.backend_feature }}
+
 
   simple-login-test:
     runs-on: ubuntu-latest
@@ -79,8 +93,8 @@ jobs:
       fail-fast: false
       matrix:
         toolchain:
-          - stable
-          - 1.41.0
+          - nightly
+          - 1.56.0
     name: test simple_login command-line example
     steps:
       - name: install expect
@@ -103,8 +117,8 @@ jobs:
       fail-fast: false
       matrix:
         toolchain:
-          - stable
-          - 1.41.0
+          - nightly
+          - 1.51.0
     name: test digital_locker command-line example
     steps:
       - name: install expect
@@ -121,26 +135,6 @@ jobs:
       - name: Run expect (which then runs cargo run)
         run: expect -f scripts/digital_locker.exp
 
-  benches:
-    name: cargo bench compilation
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout sources
-        uses: actions/checkout@v2
-
-      - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-
-      - name: Run cargo bench --no-run
-        uses: actions-rs/cargo@v1
-        with:
-          command: bench
-          args: --features "bench" --no-run
-
   clippy:
     name: cargo clippy
     runs-on: ubuntu-latest
@@ -148,11 +142,11 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v2
 
-      - name: Install stable toolchain
+      - name: Install nightly toolchain
         uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: stable
+          toolchain: nightly
           override: true
           components: rustfmt, clippy
 
@@ -170,11 +164,11 @@ jobs:
       - name: Checkout sources
         uses: actions/checkout@v2
 
-      - name: Install stable toolchain
+      - name: Install nightly toolchain
         uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: stable
+          toolchain: nightly
           override: true
           components: rustfmt, clippy
 

.gitignore

@@ -2,4 +2,5 @@
 .vscode/
 src/.DS_Store
 /target
+Cargo.lock
 **/*.rs.bk

CHANGELOG.md

@@ -1,16 +1,32 @@
 # Changelog
 
-## 0.5.1 (July 16, 2021)
+## 0.7.0 (May 13, 2023)
 
+* Update zeroize dependency to allow for beyond version 1.5
+* Increase MSRV to 1.56
+
+## 0.6.1 (January 25, 2022)
+
+* Fix `zeroize` implementing `Drop` on `enum`s now
+
+## 0.6.0 (June 30, 2021)
+
+* Synced implementation with draft-irtf-cfrg-opaque-05, which changes
+  the envelope structure and introduces a ServerSetup object to be
+  maintained by the server
 * Various security improvements: non-zero scalars, zeroizing on drop,
-  constant-time operations, reflected value check, and adding an
-  i2osp error condition
+  constant-time operations
+* Adding serde support behind a feature
+* Supporting common traits (eb59676)
+* Swapping out scrypt for argon2 (535b9b8) for the slow-hash feature
+* Adding support for common traits on public structs
+* Updated dependencies
 
-## 0.5.0 (March 1, 2020)
+## 0.5.0 (March 1, 2021)
 
 * Removed dependency on generic-bytes-derive package
 
-## 0.4.0 (February 26, 2020)
+## 0.4.0 (February 26, 2021)
 
 * Adherence to protocol format described in
   https://tools.ietf.org/html/draft-irtf-cfrg-opaque-03
@@ -19,13 +35,13 @@
 * Conformed all message type parameters to be parameterized in the
   Ciphersuite object
 
-## 0.3.1 (February 11, 2020)
+## 0.3.1 (February 11, 2021)
 
 * Re-exporting the rand library (and including it as a dependency instead of
   just rand_core)
 * Exposing a convenience function for converting from byte array to Key type
 
-## 0.3.0 (February 8, 2020)
+## 0.3.0 (February 8, 2021)
 
 * General API and documentation improvements, including the support of custom
   identifiers, optional result parameters, and the use of the export key

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "opaque-ke"
-version = "0.5.1"
+version = "0.7.0"
 repository = "https://github.com/novifinancial/opaque-ke"
 keywords = ["cryptography", "crypto", "opaque", "passwords", "authentication"]
 description = "An implementation of the OPAQUE password-authenticated key exchange protocol"
@@ -10,40 +10,37 @@ edition = "2018"
 readme = "README.md"
 
 [features]
-default = ["u64_backend"]
-slow-hash = ["scrypt"]
+default = ["u64_backend", "serialize"]
+slow-hash = ["argon2"]
 bench = []
 u64_backend = ["curve25519-dalek/u64_backend"]
 u32_backend = ["curve25519-dalek/u32_backend"]
+serialize = ["serde", "base64", "generic-array/serde", "curve25519-dalek/serde"]
 
 [dependencies]
-constant_time_eq = "0.1.5"
-curve25519-dalek = { version = "3.0.0", default-features = false, features = ["std"] }
+argon2 = { version = "0.2", optional = true }
+base64 = { version = "0.13", optional = true }
+curve25519-dalek = { version = "3.1.0", default-features = false, features = ["std"] }
 digest = "0.9.0"
 displaydoc = "0.1.7"
 generic-array = "0.14.4"
 generic-bytes = { version = "0.1.0" }
-hkdf = "0.10.0"
-hmac = "0.10.1"
+hkdf = "0.11.0"
+hmac = "0.11.0"
 rand = "0.8"
-scrypt = { version = "0.5.0", optional = true }
+serde = { version = "1", features = ["derive"], optional = true }
 subtle = { version = "2.3.0", default-features = false }
 thiserror = "1.0.22"
-zeroize = { version = "1.1.1", features = ["zeroize_derive"] }
+zeroize = { version = "1.5", features = ["zeroize_derive"] }
 
 [dev-dependencies]
 anyhow = "1.0.35"
 base64 = "0.13.0"
+bincode = "1"
 chacha20poly1305 = "0.7.1"
-criterion = "0.3.3"
 hex = "0.4.2"
 lazy_static = "1.4.0"
 serde_json = "1.0.60"
 sha2 = "0.9.2"
-proptest = "0.10.1"
-rustyline = "6.3.0"
-
-[[bench]]
-name = "oprf"
-harness = false
-required-features = ["bench"]
+proptest = "0.3"
+rustyline = "1"

README.md

@@ -14,7 +14,7 @@ OPAQUE is a PKI-free aPAKE that is secure against pre-computation attacks and ca
 Documentation
 -------------
 
-The API can be found [here](https://docs.rs/opaque-ke/) along with an example for usage.
+The API can be found [here](https://docs.rs/opaque-ke/) along with an example for usage. More examples can be found in the [examples](./examples) directory.
 
 Installation
 ------------
@@ -22,15 +22,16 @@ Installation
 Add the following line to the dependencies of your `Cargo.toml`:
 
 ```
-opaque-ke = "0.5.1"
+opaque-ke = "0.7.0"
 ```
 
 Resources
 ---------
 
 - [OPAQUE academic publication](https://eprint.iacr.org/2018/163.pdf), including formal definitions and a proof of security
-- [draft-irtf-cfrg-opaque-03](https://www.ietf.org/archive/id/draft-irtf-cfrg-opaque-03.html), containing a detailed (byte-level) specification for OPAQUE
+- [draft-irtf-cfrg-opaque-05](https://www.ietf.org/archive/id/draft-irtf-cfrg-opaque-05.html), containing a detailed (byte-level) specification for OPAQUE
 - ["Let's talk about PAKE"](https://blog.cryptographyengineering.com/2018/10/19/lets-talk-about-pake/), an introductory blog post written by Matthew Green that covers OPAQUE
+- [opaque-wasm](https://github.com/marucjmar/opaque-wasm), a WebAssembly package for this library
 
 Contributors
 ------------

benches/oprf.rs

@@ -1,68 +0,0 @@
-// Copyright (c) Facebook, Inc. and its affiliates.
-//
-// This source code is licensed under the MIT license found in the
-// LICENSE file in the root directory of this source tree.
-
-#[macro_use]
-extern crate criterion;
-
-use criterion::Criterion;
-use curve25519_dalek::ristretto::RistrettoPoint;
-use generic_array::arr;
-use opaque_ke::{
-    group::Group,
-    oprf::{blind_shim, evaluate_shim, finalize_shim},
-};
-use rand::{prelude::ThreadRng, thread_rng};
-use sha2::Sha512;
-
-fn oprf1(c: &mut Criterion) {
-    let mut csprng: ThreadRng = thread_rng();
-    let input = b"hunter2";
-
-    c.bench_function("blind with Ristretto", move |b| {
-        b.iter(|| {
-            blind_shim::<_, RistrettoPoint, Sha512>(&input[..], &mut csprng).unwrap();
-        })
-    });
-}
-
-fn oprf2(c: &mut Criterion) {
-    let mut csprng: ThreadRng = thread_rng();
-    let input = b"hunter2";
-
-    let (_, alpha) = blind_shim::<_, RistrettoPoint, Sha512>(&input[..], &mut csprng).unwrap();
-    let salt_bytes = arr![
-        u8; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
-        24, 25, 26, 27, 28, 29, 30, 31, 32,
-    ];
-    let salt = RistrettoPoint::from_scalar_slice(&salt_bytes).unwrap();
-
-    c.bench_function("evaluate with Ristretto", move |b| {
-        b.iter(|| {
-            let _beta = evaluate_shim::<RistrettoPoint>(alpha, &salt);
-        })
-    });
-}
-
-fn oprf3(c: &mut Criterion) {
-    let mut csprng: ThreadRng = thread_rng();
-    let input = b"hunter2";
-
-    let (token, alpha) = blind_shim::<_, RistrettoPoint, Sha512>(&input[..], &mut csprng).unwrap();
-    let salt_bytes = arr![
-        u8; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
-        24, 25, 26, 27, 28, 29, 30, 31, 32,
-    ];
-    let salt = RistrettoPoint::from_scalar_slice(&salt_bytes).unwrap();
-    let beta = evaluate_shim::<RistrettoPoint>(alpha, &salt);
-
-    c.bench_function("finalize with Ristretto", move |b| {
-        b.iter(|| {
-            let _res = finalize_shim::<RistrettoPoint, Sha512>(&token, beta).unwrap();
-        })
-    });
-}
-
-criterion_group!(oprf_benches, oprf1, oprf2, oprf3);
-criterion_main!(oprf_benches);

examples/digital_locker.rs

@@ -33,10 +33,10 @@ use std::process::exit;
 use opaque_ke::{
     ciphersuite::CipherSuite,
     rand::{rngs::OsRng, RngCore},
-    ClientLogin, ClientLoginFinishParameters, ClientLoginStartParameters, ClientRegistration,
+    ClientLogin, ClientLoginFinishParameters, ClientRegistration,
     ClientRegistrationFinishParameters, CredentialFinalization, CredentialRequest,
     CredentialResponse, RegistrationRequest, RegistrationResponse, RegistrationUpload, ServerLogin,
-    ServerLoginStartParameters, ServerRegistration,
+    ServerLoginStartParameters, ServerRegistration, ServerSetup,
 };
 
 // The ciphersuite trait allows to specify the underlying primitives
@@ -81,7 +81,8 @@ fn decrypt(key: &[u8], ciphertext: &[u8]) -> Vec<u8> {
 
 // Password-based registration and encryption of client secret message between a client and server
 fn register_locker(
-    server_kp: &opaque_ke::keypair::KeyPair<curve25519_dalek::ristretto::RistrettoPoint>,
+    server_setup: &ServerSetup<Default>,
+    locker_id: usize,
     password: String,
     secret_message: String,
 ) -> Locker {
@@ -91,12 +92,10 @@ fn register_locker(
     let registration_request_bytes = client_registration_start_result.message.serialize();
 
     // Client sends registration_request_bytes to server
-
-    let mut server_rng = OsRng;
     let server_registration_start_result = ServerRegistration::<Default>::start(
-        &mut server_rng,
+        &server_setup,
         RegistrationRequest::deserialize(&registration_request_bytes[..]).unwrap(),
-        server_kp.public(),
+        &locker_id.to_be_bytes(),
     )
     .unwrap();
     let registration_response_bytes = server_registration_start_result.message.serialize();
@@ -121,10 +120,9 @@ fn register_locker(
 
     // Client sends message_bytes to server
 
-    let password_file = server_registration_start_result
-        .state
-        .finish(RegistrationUpload::deserialize(&message_bytes[..]).unwrap())
-        .unwrap();
+    let password_file = ServerRegistration::finish(
+        RegistrationUpload::<Default>::deserialize(&message_bytes[..]).unwrap(),
+    );
 
     Locker {
         contents: ciphertext,
@@ -134,18 +132,15 @@ fn register_locker(
 
 // Open the contents of a locker with a password between a client and server
 fn open_locker(
-    server_kp: &opaque_ke::keypair::KeyPair<curve25519_dalek::ristretto::RistrettoPoint>,
+    server_setup: &ServerSetup<Default>,
+    locker_id: usize,
     password: String,
     locker: &Locker,
 ) -> Result<String, String> {
     let mut client_rng = OsRng;
-    let client_login_start_result = ClientLogin::<Default>::start(
-        &mut client_rng,
-        password.as_bytes(),
-        ClientLoginStartParameters::default(),
-    )
-    .unwrap();
-    let credential_request_bytes = client_login_start_result.message.serialize().unwrap();
+    let client_login_start_result =
+        ClientLogin::<Default>::start(&mut client_rng, password.as_bytes()).unwrap();
+    let credential_request_bytes = client_login_start_result.message.serialize();
 
     // Client sends credential_request_bytes to server
 
@@ -154,13 +149,14 @@ fn open_locker(
     let mut server_rng = OsRng;
     let server_login_start_result = ServerLogin::start(
         &mut server_rng,
-        password_file,
-        &server_kp.private(),
+        &server_setup,
+        Some(password_file),
         CredentialRequest::deserialize(&credential_request_bytes[..]).unwrap(),
+        &locker_id.to_be_bytes(),
         ServerLoginStartParameters::default(),
     )
     .unwrap();
-    let credential_response_bytes = server_login_start_result.message.serialize().unwrap();
+    let credential_response_bytes = server_login_start_result.message.serialize();
 
     // Server sends credential_response_bytes to client
 
@@ -174,7 +170,7 @@ fn open_locker(
         return Err(String::from("Incorrect password, please try again."));
     }
     let client_login_finish_result = result.unwrap();
-    let credential_finalization_bytes = client_login_finish_result.message.serialize().unwrap();
+    let credential_finalization_bytes = client_login_finish_result.message.serialize();
 
     // Client sends credential_finalization_bytes to server
 
@@ -200,7 +196,7 @@ fn open_locker(
 
 fn main() {
     let mut rng = OsRng;
-    let server_kp = Default::generate_random_keypair(&mut rng);
+    let server_setup = ServerSetup::<Default>::new(&mut rng);
 
     let mut rl = Editor::<()>::new();
     let mut registered_lockers: Vec<Locker> = vec![];
@@ -225,8 +221,10 @@ fn main() {
                             &mut rl,
                             None,
                         );
+                        let locker_id = registered_lockers.len();
                         registered_lockers.push(register_locker(
-                            &server_kp,
+                            &server_setup,
+                            locker_id,
                             password,
                             secret_message,
                         ));
@@ -252,7 +250,12 @@ fn main() {
                             continue;
                         }
 
-                        match open_locker(&server_kp, password, &registered_lockers[locker_index]) {
+                        match open_locker(
+                            &server_setup,
+                            locker_index,
+                            password,
+                            &registered_lockers[locker_index],
+                        ) {
                             Ok(contents) => {
                                 println!("\n\nSuccess! Contents: {}\n\n", contents);
                             }

examples/simple_login.rs

@@ -27,10 +27,9 @@ use std::process::exit;
 
 use opaque_ke::{
     ciphersuite::CipherSuite, rand::rngs::OsRng, ClientLogin, ClientLoginFinishParameters,
-    ClientLoginStartParameters, ClientRegistration, ClientRegistrationFinishParameters,
-    CredentialFinalization, CredentialRequest, CredentialResponse, RegistrationRequest,
-    RegistrationResponse, RegistrationUpload, ServerLogin, ServerLoginStartParameters,
-    ServerRegistration,
+    ClientRegistration, ClientRegistrationFinishParameters, CredentialFinalization,
+    CredentialRequest, CredentialResponse, RegistrationRequest, RegistrationResponse,
+    RegistrationUpload, ServerLogin, ServerLoginStartParameters, ServerRegistration, ServerSetup,
 };
 
 // The ciphersuite trait allows to specify the underlying primitives
@@ -46,7 +45,8 @@ impl CipherSuite for Default {
 
 // Password-based registration between a client and server
 fn account_registration(
-    server_kp: &opaque_ke::keypair::KeyPair<curve25519_dalek::ristretto::RistrettoPoint>,
+    server_setup: &ServerSetup<Default>,
+    username: String,
     password: String,
 ) -> Vec<u8> {
     let mut client_rng = OsRng;
@@ -56,11 +56,10 @@ fn account_registration(
 
     // Client sends registration_request_bytes to server
 
-    let mut server_rng = OsRng;
     let server_registration_start_result = ServerRegistration::<Default>::start(
-        &mut server_rng,
+        &server_setup,
         RegistrationRequest::deserialize(&registration_request_bytes[..]).unwrap(),
-        server_kp.public(),
+        username.as_bytes(),
     )
     .unwrap();
     let registration_response_bytes = server_registration_start_result.message.serialize();
@@ -79,27 +78,23 @@ fn account_registration(
 
     // Client sends message_bytes to server
 
-    let password_file = server_registration_start_result
-        .state
-        .finish(RegistrationUpload::deserialize(&message_bytes[..]).unwrap())
-        .unwrap();
+    let password_file = ServerRegistration::finish(
+        RegistrationUpload::<Default>::deserialize(&message_bytes[..]).unwrap(),
+    );
     password_file.serialize()
 }
 
 // Password-based login between a client and server
 fn account_login(
-    server_kp: &opaque_ke::keypair::KeyPair<curve25519_dalek::ristretto::RistrettoPoint>,
+    server_setup: &ServerSetup<Default>,
+    username: String,
     password: String,
     password_file_bytes: &[u8],
 ) -> bool {
     let mut client_rng = OsRng;
-    let client_login_start_result = ClientLogin::<Default>::start(
-        &mut client_rng,
-        password.as_bytes(),
-        ClientLoginStartParameters::default(),
-    )
-    .unwrap();
-    let credential_request_bytes = client_login_start_result.message.serialize().unwrap();
+    let client_login_start_result =
+        ClientLogin::<Default>::start(&mut client_rng, password.as_bytes()).unwrap();
+    let credential_request_bytes = client_login_start_result.message.serialize();
 
     // Client sends credential_request_bytes to server
 
@@ -107,13 +102,14 @@ fn account_login(
     let mut server_rng = OsRng;
     let server_login_start_result = ServerLogin::start(
         &mut server_rng,
-        password_file,
-        &server_kp.private(),
+        &server_setup,
+        Some(password_file),
         CredentialRequest::deserialize(&credential_request_bytes[..]).unwrap(),
+        username.as_bytes(),
         ServerLoginStartParameters::default(),
     )
     .unwrap();
-    let credential_response_bytes = server_login_start_result.message.serialize().unwrap();
+    let credential_response_bytes = server_login_start_result.message.serialize();
 
     // Server sends credential_response_bytes to client
 
@@ -127,7 +123,7 @@ fn account_login(
         return false;
     }
     let client_login_finish_result = result.unwrap();
-    let credential_finalization_bytes = client_login_finish_result.message.serialize().unwrap();
+    let credential_finalization_bytes = client_login_finish_result.message.serialize();
 
     // Client sends credential_finalization_bytes to server
 
@@ -141,7 +137,7 @@ fn account_login(
 
 fn main() {
     let mut rng = OsRng;
-    let server_kp = Default::generate_random_keypair(&mut rng);
+    let server_setup = ServerSetup::<Default>::new(&mut rng);
 
     let mut rl = Editor::<()>::new();
     let mut registered_users = HashMap::<String, Vec<u8>>::new();
@@ -164,13 +160,16 @@ fn main() {
                 let (username, password) = get_two_strings("Username", "Password", &mut rl, None);
                 match line.as_ref() {
                     "1" => {
-                        registered_users
-                            .insert(username, account_registration(&server_kp, password));
+                        registered_users.insert(
+                            username.clone(),
+                            account_registration(&server_setup, username, password),
+                        );
                         continue;
                     }
                     "2" => match registered_users.get(&username) {
                         Some(password_file_bytes) => {
-                            if account_login(&server_kp, password, password_file_bytes) {
+                            if account_login(&server_setup, username, password, password_file_bytes)
+                            {
                                 println!("\nLogin success!");
                             } else {
                                 // Note that at this point, the client knows whether or not the login

src/ciphersuite.rs

@@ -6,13 +6,11 @@
 //! Defines the CipherSuite trait to specify the underlying primitives for OPAQUE
 
 use crate::{
-    hash::Hash, key_exchange::traits::KeyExchange, keypair::KeyPair,
-    map_to_curve::GroupWithMapToCurve, slow_hash::SlowHash,
+    hash::Hash, key_exchange::traits::KeyExchange, map_to_curve::GroupWithMapToCurve,
+    slow_hash::SlowHash,
 };
 use digest::Digest;
 
-use rand::{CryptoRng, RngCore};
-
 /// Configures the underlying primitives used in OPAQUE
 /// * `Group`: a finite cyclic group along with a point representation, along
 ///   with an extension trait PasswordToCurve that allows some customization on
@@ -33,9 +31,4 @@ pub trait CipherSuite {
     type Hash: Hash;
     /// A slow hashing function, typically used for password hashing
     type SlowHash: SlowHash<Self::Hash>;
-
-    /// Generating a random key pair given a cryptographic rng
-    fn generate_random_keypair<R: RngCore + CryptoRng>(rng: &mut R) -> KeyPair<Self::Group> {
-        KeyPair::<Self::Group>::generate_random(rng)
-    }
 }

src/envelope.rs

@@ -4,10 +4,13 @@
 // LICENSE file in the root directory of this source tree.
 
 use crate::{
-    errors::{utils::check_slice_size_atleast, InternalPakeError, PakeError, ProtocolError},
+    ciphersuite::CipherSuite,
+    errors::{utils::check_slice_size, InternalPakeError, PakeError, ProtocolError},
+    group::Group,
     hash::Hash,
-    keypair::Key,
-    serialization::serialize,
+    keypair::{KeyPair, PrivateKey, PublicKey},
+    map_to_curve::GroupWithMapToCurve,
+    opaque::{bytestrings_from_identifiers, Identifiers},
 };
 use digest::Digest;
 use generic_array::{typenum::Unsigned, GenericArray};
@@ -19,80 +22,62 @@ use std::convert::TryFrom;
 use zeroize::Zeroize;
 
 // Constant string used as salt for HKDF computation
-const STR_PAD: &[u8] = b"Pad";
 const STR_AUTH_KEY: &[u8] = b"AuthKey";
 const STR_EXPORT_KEY: &[u8] = b"ExportKey";
+const STR_PRIVATE_KEY: &[u8] = b"PrivateKey";
+const STR_OPAQUE_HASH_TO_SCALAR: &[u8] = b"OPAQUE-HashToScalar";
 
 const NONCE_LEN: usize = 32;
 
-#[derive(Clone, Copy, PartialEq, Zeroize)]
+fn build_inner_envelope_internal<CS: CipherSuite>(
+    random_pwd: &[u8],
+    nonce: &[u8],
+) -> Result<PublicKey, InternalPakeError> {
+    let h = Hkdf::<CS::Hash>::new(None, random_pwd);
+    let mut keypair_seed = vec![0u8; <PrivateKey as SizedBytes>::Len::to_usize()];
+    h.expand(&[nonce, STR_PRIVATE_KEY].concat(), &mut keypair_seed)
+        .map_err(|_| InternalPakeError::HkdfError)?;
+    let client_static_keypair =
+        KeyPair::<CS::Group>::from_private_key_slice(CS::Group::scalar_as_bytes(
+            &CS::Group::hash_to_scalar::<CS::Hash>(&keypair_seed[..], STR_OPAQUE_HASH_TO_SCALAR)?,
+        ))?;
+
+    Ok(client_static_keypair.public().clone())
+}
+
+fn recover_keys_internal<CS: CipherSuite>(
+    random_pwd: &[u8],
+    nonce: &[u8],
+) -> Result<KeyPair<CS::Group>, InternalPakeError> {
+    let h = Hkdf::<CS::Hash>::new(None, random_pwd);
+    let mut keypair_seed = vec![0u8; <PrivateKey as SizedBytes>::Len::to_usize()];
+    h.expand(&[nonce, STR_PRIVATE_KEY].concat(), &mut keypair_seed)
+        .map_err(|_| InternalPakeError::HkdfError)?;
+    let client_static_keypair =
+        KeyPair::<CS::Group>::from_private_key_slice(CS::Group::scalar_as_bytes(
+            &CS::Group::hash_to_scalar::<CS::Hash>(&keypair_seed[..], STR_OPAQUE_HASH_TO_SCALAR)?,
+        ))?;
+
+    Ok(client_static_keypair)
+}
+
+#[derive(Clone, Debug, Eq, Hash, PartialEq, Zeroize)]
 #[zeroize(drop)]
 pub(crate) enum InnerEnvelopeMode {
-    Base = 1,
-    CustomIdentifier = 2,
+    Zero = 0,
+    Internal = 1,
 }
 
 impl TryFrom<u8> for InnerEnvelopeMode {
     type Error = PakeError;
     fn try_from(x: u8) -> Result<Self, Self::Error> {
         match x {
-            1 => Ok(InnerEnvelopeMode::Base),
-            2 => Ok(InnerEnvelopeMode::CustomIdentifier),
+            1 => Ok(InnerEnvelopeMode::Internal),
             _ => Err(PakeError::SerializationError),
         }
     }
 }
 
-#[derive(Clone, Zeroize)]
-#[zeroize(drop)]
-pub(crate) struct InnerEnvelope {
-    mode: InnerEnvelopeMode,
-    nonce: Vec<u8>,
-    ciphertext: Vec<u8>,
-}
-
-impl InnerEnvelope {
-    pub(crate) fn serialize(&self) -> Vec<u8> {
-        [&[self.mode as u8], &self.nonce[..], &self.ciphertext[..]].concat()
-    }
-
-    pub(crate) fn deserialize(input: &[u8]) -> Result<(Self, Vec<u8>), ProtocolError> {
-        if input.is_empty() {
-            return Err(ProtocolError::VerificationError(
-                PakeError::SerializationError,
-            ));
-        }
-        let mode = InnerEnvelopeMode::try_from(input[0])?;
-
-        let key_len = <Key as SizedBytes>::Len::to_usize();
-
-        let bytes = &input[1..];
-        if bytes.len() < NONCE_LEN + key_len {
-            return Err(ProtocolError::VerificationError(
-                PakeError::SerializationError,
-            ));
-        }
-
-        Ok((
-            Self {
-                mode,
-                nonce: bytes[..NONCE_LEN].to_vec(),
-                ciphertext: bytes[NONCE_LEN..NONCE_LEN + key_len].to_vec(),
-            },
-            bytes[NONCE_LEN + key_len..].to_vec(),
-        ))
-    }
-
-    #[cfg(test)]
-    pub fn as_byte_ptrs(&self) -> Vec<(*const u8, usize)> {
-        vec![
-            /* Cannot easily get raw pointer of enum value, otherwise would do self.mode.as_ptr() */
-            (self.nonce.as_ptr(), self.nonce.len()),
-            (self.ciphertext.as_ptr(), self.ciphertext.len()),
-        ]
-    }
-}
-
 /// This struct is an instantiation of the envelope as described in
 /// https://tools.ietf.org/html/draft-krawczyk-cfrg-opaque-06#section-4
 ///
@@ -103,131 +88,153 @@ impl InnerEnvelope {
 /// The specification update has simplified this assumption by taking
 /// an XOR-based approach without compromising on security, and to avoid
 /// the confusion around the implementation of an RKR-secure encryption.
-#[derive(Clone)]
-pub(crate) struct Envelope<D: Hash> {
-    inner_envelope: InnerEnvelope,
-    hmac: GenericArray<u8, <D as Digest>::OutputSize>,
+pub(crate) struct Envelope<CS: CipherSuite> {
+    mode: InnerEnvelopeMode,
+    nonce: Vec<u8>,
+    hmac: GenericArray<u8, <CS::Hash as Digest>::OutputSize>,
 }
 
+// Cannot be derived because it would require for CS to be Clone.
+impl<CS: CipherSuite> Clone for Envelope<CS> {
+    fn clone(&self) -> Self {
+        Self {
+            mode: self.mode.clone(),
+            nonce: self.nonce.clone(),
+            hmac: self.hmac.clone(),
+        }
+    }
+}
+
+impl_debug_eq_hash_for!(struct Envelope<CS: CipherSuite>, [mode, nonce, hmac]);
+
 // Note that this struct represents an envelope that has been "opened" with the asssociated
 // key. This key is also used to derive the export_key parameter, which is technically
 // unrelated to the envelope's encrypted and authenticated contents.
-pub(crate) struct OpenedEnvelope<D: Hash> {
-    pub(crate) client_s_sk: Vec<u8>,
-    pub(crate) export_key: GenericArray<u8, <D as Digest>::OutputSize>,
+pub(crate) struct OpenedEnvelope<CS: CipherSuite> {
+    pub(crate) client_static_keypair: KeyPair<CS::Group>,
+    pub(crate) export_key: GenericArray<u8, <CS::Hash as Digest>::OutputSize>,
+    pub(crate) id_u: Vec<u8>,
+    pub(crate) id_s: Vec<u8>,
 }
 
 pub(crate) struct OpenedInnerEnvelope<D: Hash> {
-    pub(crate) plaintext: Vec<u8>,
     pub(crate) export_key: GenericArray<u8, <D as Digest>::OutputSize>,
 }
 
-impl<D: Hash> Envelope<D> {
+impl<CS: CipherSuite> Envelope<CS> {
     fn hmac_key_size() -> usize {
-        <D as Digest>::OutputSize::to_usize()
+        <CS::Hash as Digest>::OutputSize::to_usize()
     }
 
     fn export_key_size() -> usize {
-        <D as Digest>::OutputSize::to_usize()
+        <CS::Hash as Digest>::OutputSize::to_usize()
     }
 
-    pub(crate) fn get_mode(&self) -> InnerEnvelopeMode {
-        self.inner_envelope.mode
-    }
-
-    /// The format of the output is:
-    /// mode | nonce             | ciphertext       | hmac
-    /// u8   | nonce_size bytes  | variable length  | hmac_size bytes
-    pub(crate) fn from_bytes(bytes: &[u8]) -> Result<Self, InternalPakeError> {
-        let (result, remainder) = Self::deserialize(bytes)
-            .map_err(|_| InternalPakeError::InvalidEnvelopeStructureError)?;
-        if !remainder.is_empty() {
-            return Err(InternalPakeError::InvalidEnvelopeStructureError);
-        }
-        Ok(result)
-    }
-
-    pub(crate) fn to_bytes(&self) -> Vec<u8> {
-        self.serialize()
+    pub(crate) fn len() -> usize {
+        <CS::Hash as Digest>::OutputSize::to_usize() + NONCE_LEN
     }
 
     pub(crate) fn serialize(&self) -> Vec<u8> {
-        [&self.inner_envelope.serialize(), &self.hmac[..]].concat()
+        [&self.nonce[..], &self.hmac[..]].concat()
     }
+    pub(crate) fn deserialize(bytes: &[u8]) -> Result<Self, ProtocolError> {
+        let mode = InnerEnvelopeMode::Internal; // Better way to hard-code this?
 
-    pub(crate) fn deserialize(input: &[u8]) -> Result<(Self, Vec<u8>), ProtocolError> {
-        let (inner_envelope, remainder) = InnerEnvelope::deserialize(input)?;
+        if bytes.len() < NONCE_LEN {
+            return Err(ProtocolError::VerificationError(
+                PakeError::SerializationError,
+            ));
+        }
+        let nonce = bytes[..NONCE_LEN].to_vec();
+
+        let remainder = match mode {
+            InnerEnvelopeMode::Zero => {
+                return Err(InternalPakeError::IncompatibleEnvelopeModeError.into())
+            }
+            InnerEnvelopeMode::Internal => bytes[NONCE_LEN..].to_vec(),
+        };
 
         let hmac_key_size = Self::hmac_key_size();
-        let hmac_and_remainder =
-            check_slice_size_atleast(&remainder, hmac_key_size, "hmac_key_size")?;
+        let hmac = check_slice_size(&remainder, hmac_key_size, "hmac_key_size")?;
 
-        Ok((
-            Self {
-                inner_envelope,
-                hmac: GenericArray::clone_from_slice(&hmac_and_remainder[..hmac_key_size]),
-            },
-            hmac_and_remainder[hmac_key_size..].to_vec(),
-        ))
+        Ok(Self {
+            mode,
+            nonce,
+            hmac: GenericArray::clone_from_slice(hmac),
+        })
     }
 
+    // Creates a dummy envelope object that serializes to the all-zeros byte string
+    pub(crate) fn dummy() -> Self {
+        Self {
+            mode: InnerEnvelopeMode::Zero,
+            nonce: vec![0u8; NONCE_LEN],
+            hmac: GenericArray::clone_from_slice(&vec![
+                0u8;
+                <CS::Hash as Digest>::OutputSize::to_usize()
+            ]),
+        }
+    }
+
+    #[allow(clippy::type_complexity)]
     pub(crate) fn seal<R: RngCore + CryptoRng>(
         rng: &mut R,
         key: &[u8],
-        client_s_sk: &[u8],
         server_s_pk: &[u8],
-        optional_ids: Option<(Vec<u8>, Vec<u8>)>,
-    ) -> Result<(Self, GenericArray<u8, <D as Digest>::OutputSize>), ProtocolError> {
-        let aad = construct_aad(server_s_pk, &optional_ids)?;
-        Self::seal_raw(rng, key, &client_s_sk, &aad, mode_from_ids(&optional_ids))
+        optional_ids: Option<Identifiers>,
+    ) -> Result<
+        (
+            Self,
+            PublicKey,
+            GenericArray<u8, <CS::Hash as Digest>::OutputSize>,
+        ),
+        InternalPakeError,
+    > {
+        let mut nonce = vec![0u8; NONCE_LEN];
+        rng.fill_bytes(&mut nonce);
+
+        let (mode, client_s_pk) = (
+            InnerEnvelopeMode::Internal,
+            build_inner_envelope_internal::<CS>(key, &nonce)?,
+        );
+
+        let (id_u, id_s) =
+            bytestrings_from_identifiers(&optional_ids, &client_s_pk.to_arr(), server_s_pk);
+        let aad = construct_aad(&id_u, &id_s, server_s_pk);
+
+        let (envelope, export_key) = Self::seal_raw(key, &nonce, &aad, mode)?;
+        Ok((envelope, client_s_pk, export_key))
     }
 
     /// Uses a key to convert the plaintext into an envelope, authenticated by the aad field.
     /// Note that a new nonce is sampled for each call to seal.
-    pub(crate) fn seal_raw<R: RngCore + CryptoRng>(
-        rng: &mut R,
+    #[allow(clippy::type_complexity)]
+    pub(crate) fn seal_raw(
         key: &[u8],
-        plaintext: &[u8],
+        nonce: &[u8],
         aad: &[u8],
         mode: InnerEnvelopeMode,
-    ) -> Result<(Self, GenericArray<u8, <D as Digest>::OutputSize>), ProtocolError> {
-        let mut nonce = vec![0u8; NONCE_LEN];
-        rng.fill_bytes(&mut nonce);
-
-        let h = Hkdf::<D>::new(Some(&nonce), &key);
-        let mut xor_key = vec![0u8; plaintext.len()];
+    ) -> Result<(Self, GenericArray<u8, <CS::Hash as Digest>::OutputSize>), InternalPakeError> {
+        let h = Hkdf::<CS::Hash>::new(None, key);
         let mut hmac_key = vec![0u8; Self::hmac_key_size()];
         let mut export_key = vec![0u8; Self::export_key_size()];
 
-        h.expand(STR_PAD, &mut xor_key)
+        h.expand(&[nonce, STR_AUTH_KEY].concat(), &mut hmac_key)
             .map_err(|_| InternalPakeError::HkdfError)?;
-        h.expand(STR_AUTH_KEY, &mut hmac_key)
-            .map_err(|_| InternalPakeError::HkdfError)?;
-        h.expand(STR_EXPORT_KEY, &mut export_key)
+        h.expand(&[nonce, STR_EXPORT_KEY].concat(), &mut export_key)
             .map_err(|_| InternalPakeError::HkdfError)?;
 
-        let ciphertext: Vec<u8> = xor_key
-            .iter()
-            .zip(plaintext.iter())
-            .map(|(&x1, &x2)| x1 ^ x2)
-            .collect();
-
-        let inner_envelope = InnerEnvelope {
-            mode,
-            nonce,
-            ciphertext,
-        };
-
-        let mut hmac =
-            Hmac::<D>::new_varkey(&hmac_key).map_err(|_| InternalPakeError::HmacError)?;
-        hmac.update(&inner_envelope.serialize());
-        hmac.update(&aad);
+        let mut hmac = Hmac::<CS::Hash>::new_from_slice(&hmac_key)
+            .map_err(|_| InternalPakeError::HmacError)?;
+        hmac.update(nonce);
+        hmac.update(aad);
 
         let hmac_bytes = hmac.finalize().into_bytes();
 
         Ok((
             Self {
-                inner_envelope,
+                mode,
+                nonce: nonce.to_vec(),
                 hmac: hmac_bytes,
             },
             GenericArray::clone_from_slice(&export_key),
@@ -238,24 +245,29 @@ impl<D: Hash> Envelope<D> {
         &self,
         key: &[u8],
         server_s_pk: &[u8],
-        optional_ids: &Option<(Vec<u8>, Vec<u8>)>,
-    ) -> Result<OpenedEnvelope<D>, ProtocolError> {
-        // First, check that mode matches
-        if self.inner_envelope.mode != mode_from_ids(optional_ids) {
-            return Err(InternalPakeError::IncompatibleEnvelopeModeError.into());
-        }
+        optional_ids: &Option<Identifiers>,
+    ) -> Result<OpenedEnvelope<CS>, InternalPakeError> {
+        let client_static_keypair = match self.mode {
+            InnerEnvelopeMode::Zero => {
+                return Err(InternalPakeError::IncompatibleEnvelopeModeError)
+            }
+            InnerEnvelopeMode::Internal => recover_keys_internal::<CS>(key, &self.nonce)?,
+        };
+
+        let (id_u, id_s) = bytestrings_from_identifiers(
+            optional_ids,
+            &client_static_keypair.public().to_arr(),
+            server_s_pk,
+        );
+        let aad = construct_aad(&id_u, &id_s, server_s_pk);
 
-        let aad = construct_aad(server_s_pk, optional_ids)?;
         let opened = self.open_raw(key, &aad)?;
 
-        if opened.plaintext.len() != <Key as SizedBytes>::Len::to_usize() {
-            // Plaintext should consist of a single key
-            return Err(InternalPakeError::UnexpectedEnvelopeContentsError.into());
-        }
-
         Ok(OpenedEnvelope {
-            client_s_sk: opened.plaintext,
+            client_static_keypair,
             export_key: opened.export_key,
+            id_u,
+            id_s,
         })
     }
 
@@ -265,35 +277,26 @@ impl<D: Hash> Envelope<D> {
         &self,
         key: &[u8],
         aad: &[u8],
-    ) -> Result<OpenedInnerEnvelope<D>, InternalPakeError> {
-        let h = Hkdf::<D>::new(Some(&self.inner_envelope.nonce), &key);
-        let mut xor_key = vec![0u8; self.inner_envelope.ciphertext.len()];
+    ) -> Result<OpenedInnerEnvelope<CS::Hash>, InternalPakeError> {
+        let h = Hkdf::<CS::Hash>::new(None, key);
         let mut hmac_key = vec![0u8; Self::hmac_key_size()];
         let mut export_key = vec![0u8; Self::export_key_size()];
 
-        h.expand(STR_PAD, &mut xor_key)
+        h.expand(&[&self.nonce, STR_AUTH_KEY].concat(), &mut hmac_key)
             .map_err(|_| InternalPakeError::HkdfError)?;
-        h.expand(STR_AUTH_KEY, &mut hmac_key)
-            .map_err(|_| InternalPakeError::HkdfError)?;
-        h.expand(STR_EXPORT_KEY, &mut export_key)
+        h.expand(&[&self.nonce, STR_EXPORT_KEY].concat(), &mut export_key)
             .map_err(|_| InternalPakeError::HkdfError)?;
 
-        let mut hmac =
-            Hmac::<D>::new_varkey(&hmac_key).map_err(|_| InternalPakeError::HmacError)?;
-        hmac.update(&self.inner_envelope.serialize());
+        let mut hmac = Hmac::<CS::Hash>::new_from_slice(&hmac_key)
+            .map_err(|_| InternalPakeError::HmacError)?;
+        hmac.update(&self.nonce);
         hmac.update(aad);
         if hmac.verify(&self.hmac).is_err() {
             return Err(InternalPakeError::SealOpenHmacError);
         }
 
-        let plaintext: Vec<u8> = xor_key
-            .iter()
-            .zip(self.inner_envelope.ciphertext.iter())
-            .map(|(&x1, &x2)| x1 ^ x2)
-            .collect();
         Ok(OpenedInnerEnvelope {
-            plaintext,
-            export_key: GenericArray::<u8, <D as Digest>::OutputSize>::clone_from_slice(
+            export_key: GenericArray::<u8, <CS::Hash as Digest>::OutputSize>::clone_from_slice(
                 &export_key,
             ),
         })
@@ -301,23 +304,20 @@ impl<D: Hash> Envelope<D> {
 
     #[cfg(test)]
     pub fn as_byte_ptrs(&self) -> Vec<(*const u8, usize)> {
-        [
-            self.inner_envelope.as_byte_ptrs(),
-            vec![(self.hmac.as_ptr(), self.hmac.len())],
-        ]
-        .concat()
+        vec![(self.hmac.as_ptr(), self.hmac.len())]
     }
 }
 
 // This can't be derived because of the use of a phantom parameter
-impl<D: Hash> Zeroize for Envelope<D> {
+impl<CS: CipherSuite> Zeroize for Envelope<CS> {
     fn zeroize(&mut self) {
-        self.inner_envelope.zeroize();
+        self.mode.zeroize();
+        self.nonce.zeroize();
         self.hmac.zeroize();
     }
 }
 
-impl<D: Hash> Drop for Envelope<D> {
+impl<CS: CipherSuite> Drop for Envelope<CS> {
     fn drop(&mut self) {
         self.zeroize();
     }
@@ -325,48 +325,6 @@ impl<D: Hash> Drop for Envelope<D> {
 
 // Helper functions
 
-fn construct_aad(
-    server_s_pk: &[u8],
-    optional_ids: &Option<(Vec<u8>, Vec<u8>)>,
-) -> Result<Vec<u8>, ProtocolError> {
-    let ids = match optional_ids {
-        Some((l, r)) => [serialize(l, 2)?, serialize(r, 2)?].concat(),
-        None => vec![],
-    };
-    Ok([server_s_pk.to_vec(), ids].concat())
-}
-
-pub(crate) fn mode_from_ids(optional_ids: &Option<(Vec<u8>, Vec<u8>)>) -> InnerEnvelopeMode {
-    match optional_ids {
-        Some(_) => InnerEnvelopeMode::CustomIdentifier,
-        None => InnerEnvelopeMode::Base,
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use rand::rngs::OsRng;
-
-    #[test]
-    fn seal_and_open() {
-        let mut rng = OsRng;
-        let mut key = [0u8; 32];
-        rng.fill_bytes(&mut key);
-
-        let mut msg = [0u8; 100];
-        rng.fill_bytes(&mut msg);
-
-        let (envelope, export_key_1) = Envelope::<sha2::Sha256>::seal_raw(
-            &mut rng,
-            &key,
-            &msg,
-            b"aad",
-            InnerEnvelopeMode::Base,
-        )
-        .unwrap();
-        let opened_envelope = envelope.open_raw(&key, b"aad").unwrap();
-        assert_eq!(&msg.to_vec(), &opened_envelope.plaintext);
-        assert_eq!(&export_key_1.to_vec(), &opened_envelope.export_key.to_vec());
-    }
+fn construct_aad(id_u: &[u8], id_s: &[u8], server_s_pk: &[u8]) -> Vec<u8> {
+    [server_s_pk, id_s, id_u].concat()
 }

src/errors.rs

@@ -8,7 +8,7 @@ use displaydoc::Display;
 use thiserror::Error;
 
 /// Represents an error in the manipulation of internal cryptographic data
-#[derive(Debug, Display, Error)]
+#[derive(Clone, Debug, Display, Error, Eq, Hash, PartialEq)]
 pub enum InternalPakeError {
     /// Deserializing from a byte sequence failed
     InvalidByteSequence,
@@ -56,7 +56,7 @@ pub enum InternalPakeError {
 }
 
 /// Represents an error in password checking
-#[derive(Debug, Display, Error)]
+#[derive(Clone, Debug, Display, Error, Eq, Hash, PartialEq)]
 pub enum PakeError {
     /// This error results from an internal error during PRF construction
     ///
@@ -86,12 +86,14 @@ impl From<InternalPakeError> for PakeError {
 }
 
 /// Represents an error in protocol handling
-#[derive(Debug, Display, Error)]
+#[derive(Clone, Debug, Display, Error, Eq, Hash, PartialEq)]
 pub enum ProtocolError {
     /// This error results from an error during password verification
     ///
     /// Internal error during password verification: {0}
     VerificationError(PakeError),
+    /// This error occurs when the inner envelope is malformed
+    InvalidInnerEnvelopeError,
     /// This error occurs when the server answer cannot be handled
     /// Server response cannot be handled.
     ServerError,
@@ -101,9 +103,6 @@ pub enum ProtocolError {
     /// This error occurs when the client request cannot be handled
     /// Client request cannot be handled.
     ClientError,
-    /// This error occurs when the client detects that the server has
-    /// reflected the OPRF value (beta == alpha)
-    ReflectedValueError,
 }
 
 // This is meant to express future(ly) non-trivial ways of converting the

src/group.rs

@@ -68,9 +68,6 @@ pub trait Group: Copy + Sized + for<'a> Mul<&'a <Self as Group>::Scalar, Output
 
     /// Returns if the group element is equal to the identity (1)
     fn is_identity(&self) -> bool;
-
-    /// Compares in constant time if the group elements are equal
-    fn ct_equal(&self, other: &Self) -> bool;
 }
 
 /// The implementation of such a subgroup for Ristretto
@@ -154,8 +151,4 @@ impl Group for RistrettoPoint {
     fn is_identity(&self) -> bool {
         self == &Self::identity()
     }
-
-    fn ct_equal(&self, other: &Self) -> bool {
-        constant_time_eq::constant_time_eq(&self.to_arr(), &other.to_arr())
-    }
 }

src/impls.rs

@@ -0,0 +1,102 @@
+// Copyright (c) Facebook, Inc. and its affiliates.
+//
+// This source code is licensed under the MIT license found in the
+// LICENSE file in the root directory of this source tree.
+
+macro_rules! impl_debug_eq_hash_for {
+    (struct $name:ident$(<$($gen:ident$(: $bound:tt)?),+$(,)?>)?, [$field1:ident$(, $field2:ident)*$(,)?]$(, )?$([$($type:ty),+$(,)?]$(,)?)?) => {
+        impl$(<$($gen$(: $bound)?),+>)? std::fmt::Debug for $name$(<$($gen),+>)?
+        $(where $($type: std::fmt::Debug,)+)?
+        {
+            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                f.debug_struct("$name")
+                .field("$field1", &self.$field1)
+                $(.field("$field2", &self.$field2))*
+                .finish()
+            }
+        }
+
+        impl$(<$($gen$(: $bound)?),+>)? Eq for $name$(<$($gen),+>)?
+        $(where $($type: Eq,)+)?
+        {}
+
+        impl$(<$($gen$(: $bound)?),+>)? PartialEq for $name$(<$($gen),+>)?
+        $(where $($type: PartialEq,)+)?
+        {
+            fn eq(&self, other: &Self) -> bool {
+                PartialEq::eq(&self.$field1, &other.$field1)
+                $(&& PartialEq::eq(&self.$field2, &other.$field2))*
+            }
+        }
+
+        impl$(<$($gen$(: $bound)?),+>)? std::hash::Hash for $name$(<$($gen),+>)?
+        $(where $($type: std::hash::Hash,)+)?
+        {
+            fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+                std::hash::Hash::hash(&self.$field1, state);
+                $(std::hash::Hash::hash(&self.$field2, state);)*
+            }
+        }
+    };
+    (tuple $name:ident$(<$($gen:ident$(: $bound:tt)?),+$(,)?>)?, [$field1:tt$(, $field2:tt)*$(,)?]$(, )?$([$($type:ty),+$(,)?]$(,)?)?) => {
+        impl$(<$($gen$(: $bound)?),+>)? std::fmt::Debug for $name$(<$($gen),+>)?
+        $(where $($type: std::fmt::Debug,)+)?
+        {
+            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                f.debug_tuple("$name")
+                .field(&self.$field1)
+                $(.field(&self.$field2))*
+                .finish()
+            }
+        }
+
+        impl$(<$($gen$(: $bound)?),+>)? Eq for $name$(<$($gen),+>)?
+        $(where $($type: Eq,)+)?
+        {}
+
+        impl$(<$($gen$(: $bound)?),+>)? PartialEq for $name$(<$($gen),+>)?
+        $(where $($type: PartialEq,)+)?
+        {
+            fn eq(&self, other: &Self) -> bool {
+                PartialEq::eq(&self.$field1, &other.$field1)
+                $(&& PartialEq::eq(&self.$field2, &other.$field2))*
+            }
+        }
+
+        impl$(<$($gen$(: $bound)?),+>)? std::hash::Hash for $name$(<$($gen),+>)?
+        $(where $($type: std::hash::Hash,)+)?
+        {
+            fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+                std::hash::Hash::hash(&self.$field1, state);
+                $(std::hash::Hash::hash(&self.$field2, state);)*
+            }
+        }
+    };
+}
+
+macro_rules! impl_clone_for {
+    (struct $name:ident$(<$($gen:ident$(: $bound:tt)?),+$(,)?>)?, [$field1:ident$(, $field2:ident)*$(,)?]$(, )?$([$($type:ty),+$(,)?]$(,)?)?) => {
+        impl$(<$($gen$(: $bound)?),+>)? Clone for $name$(<$($gen),+>)?
+        $(where $($type: Clone,)+)?
+        {
+            fn clone(&self) -> Self {
+                Self {
+                    $field1: self.$field1.clone(),
+                    $($field2: self.$field2.clone(),)*
+                }
+            }
+        }
+    };
+    (tuple $name:ident$(<$($gen:ident$(: $bound:tt)?),+$(,)?>)?, [$field1:tt$(, $field2:tt)*$(,)?]$(, )?$([$($type:ty),+$(,)?]$(,)?)?) => {
+        impl$(<$($gen$(: $bound)?),+>)? Clone for $name$(<$($gen),+>)?
+        $(where $($type: Clone,)+)?
+        {
+            fn clone(&self) -> Self {
+                Self(
+                    self.$field1.clone(),
+                    $(self.$field2.clone(),)*
+                )
+            }
+        }
+    };
+}

src/key_exchange/traits.rs

@@ -4,25 +4,23 @@
 // LICENSE file in the root directory of this source tree.
 
 use crate::{
+    ciphersuite::CipherSuite,
     errors::{PakeError, ProtocolError},
     group::Group,
     hash::Hash,
-    keypair::Key,
+    keypair::{PrivateKey, PublicKey},
 };
 use rand::{CryptoRng, RngCore};
-
-use std::convert::TryFrom;
 use zeroize::Zeroize;
 
 pub trait KeyExchange<D: Hash, G: Group> {
-    type KE1State: for<'r> TryFrom<&'r [u8], Error = PakeError> + ToBytesWithPointers + Zeroize;
-    type KE2State: for<'r> TryFrom<&'r [u8], Error = PakeError> + ToBytesWithPointers + Zeroize;
-    type KE1Message: for<'r> TryFrom<&'r [u8], Error = PakeError> + ToBytes;
-    type KE2Message: for<'r> TryFrom<&'r [u8], Error = PakeError> + ToBytes + Clone;
-    type KE3Message: for<'r> TryFrom<&'r [u8], Error = PakeError> + ToBytes;
+    type KE1State: FromBytes + ToBytesWithPointers + Zeroize + Clone;
+    type KE2State: FromBytes + ToBytesWithPointers + Zeroize + Clone;
+    type KE1Message: FromBytes + ToBytes + Clone;
+    type KE2Message: FromBytes + ToBytes + Clone;
+    type KE3Message: FromBytes + ToBytes + Clone;
 
     fn generate_ke1<R: RngCore + CryptoRng>(
-        info: Vec<u8>,
         rng: &mut R,
     ) -> Result<(Self::KE1State, Self::KE1Message), ProtocolError>;
 
@@ -32,12 +30,12 @@ pub trait KeyExchange<D: Hash, G: Group> {
         l1_bytes: Vec<u8>,
         l2_bytes: Vec<u8>,
         ke1_message: Self::KE1Message,
-        client_s_pk: Key,
-        server_s_sk: Key,
+        client_s_pk: PublicKey,
+        server_s_sk: PrivateKey,
         id_u: Vec<u8>,
         id_s: Vec<u8>,
-        e_info: Vec<u8>,
-    ) -> Result<(Vec<u8>, Self::KE2State, Self::KE2Message), ProtocolError>;
+        context: Vec<u8>,
+    ) -> Result<(Self::KE2State, Self::KE2Message), ProtocolError>;
 
     #[allow(clippy::too_many_arguments, clippy::type_complexity)]
     fn generate_ke3(
@@ -45,11 +43,12 @@ pub trait KeyExchange<D: Hash, G: Group> {
         ke2_message: Self::KE2Message,
         ke1_state: &Self::KE1State,
         serialized_credential_request: &[u8],
-        server_s_pk: Key,
-        client_s_sk: Key,
+        server_s_pk: PublicKey,
+        client_s_sk: PrivateKey,
         id_u: Vec<u8>,
         id_s: Vec<u8>,
-    ) -> Result<(Vec<u8>, Vec<u8>, Self::KE3Message), ProtocolError>;
+        context: Vec<u8>,
+    ) -> Result<(Vec<u8>, Self::KE3Message), ProtocolError>;
 
     #[allow(clippy::type_complexity)]
     fn finish_ke(
@@ -60,12 +59,16 @@ pub trait KeyExchange<D: Hash, G: Group> {
     fn ke2_message_size() -> usize;
 }
 
+pub trait FromBytes: Sized {
+    fn from_bytes<CS: CipherSuite>(input: &[u8]) -> Result<Self, PakeError>;
+}
+
 pub trait ToBytes {
-    fn to_bytes(&self) -> Result<Vec<u8>, ProtocolError>;
+    fn to_bytes(&self) -> Vec<u8>;
 }
 
 pub trait ToBytesWithPointers {
-    fn to_bytes(&self) -> Result<Vec<u8>, ProtocolError>;
+    fn to_bytes(&self) -> Vec<u8>;
 
     // Only used for tests to grab raw pointers to data
     #[cfg(test)]

src/key_exchange/tripledh.rs

@@ -5,15 +5,16 @@
 
 //! An implementation of the Triple Diffie-Hellman key exchange protocol
 use crate::{
+    ciphersuite::CipherSuite,
     errors::{
         utils::{check_slice_size, check_slice_size_atleast},
         InternalPakeError, PakeError, ProtocolError,
     },
     group::Group,
     hash::Hash,
-    key_exchange::traits::{KeyExchange, ToBytes, ToBytesWithPointers},
-    keypair::{Key, KeyPair, SizedBytesExt},
-    serialization::{serialize, tokenize},
+    key_exchange::traits::{FromBytes, KeyExchange, ToBytes, ToBytesWithPointers},
+    keypair::{KeyPair, PrivateKey, PublicKey, SizedBytesExt},
+    serialization::serialize,
 };
 use digest::{Digest, FixedOutput};
 use generic_array::{
@@ -30,14 +31,12 @@ use zeroize::Zeroize;
 const KEY_LEN: usize = 32;
 pub(crate) type NonceLen = U32;
 
-static STR_3DH: &[u8] = b"3DH";
-static STR_CLIENT_MAC: &[u8] = b"client mac";
-static STR_HANDSHAKE_SECRET: &[u8] = b"handshake secret";
-static STR_SERVER_MAC: &[u8] = b"server mac";
-static STR_HANDSHAKE_ENC: &[u8] = b"handshake enc";
-static STR_ENCRYPTION_PAD: &[u8] = b"encryption pad";
-static STR_SESSION_SECRET: &[u8] = b"session secret";
-static STR_OPAQUE: &[u8] = b"OPAQUE ";
+static STR_RFC: &[u8] = b"RFCXXXX";
+static STR_CLIENT_MAC: &[u8] = b"ClientMAC";
+static STR_HANDSHAKE_SECRET: &[u8] = b"HandshakeSecret";
+static STR_SERVER_MAC: &[u8] = b"ServerMAC";
+static STR_SESSION_KEY: &[u8] = b"SessionKey";
+static STR_OPAQUE: &[u8] = b"OPAQUE-";
 
 #[allow(clippy::upper_case_acronyms)]
 /// The Triple Diffie-Hellman key exchange implementation
@@ -51,7 +50,6 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
     type KE3Message = Ke3Message<<D as FixedOutput>::OutputSize>;
 
     fn generate_ke1<R: RngCore + CryptoRng>(
-        info: Vec<u8>,
         rng: &mut R,
     ) -> Result<(Self::KE1State, Self::KE1Message), ProtocolError> {
         let client_e_kp = KeyPair::<G>::generate_random(rng);
@@ -59,7 +57,6 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
 
         let ke1_message = Ke1Message {
             client_nonce,
-            info,
             client_e_pk: client_e_kp.public().clone(),
         };
 
@@ -78,25 +75,26 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
         serialized_credential_request: Vec<u8>,
         l2_bytes: Vec<u8>,
         ke1_message: Self::KE1Message,
-        client_s_pk: Key,
-        server_s_sk: Key,
+        client_s_pk: PublicKey,
+        server_s_sk: PrivateKey,
         id_u: Vec<u8>,
         id_s: Vec<u8>,
-        e_info: Vec<u8>,
-    ) -> Result<(Vec<u8>, Self::KE2State, Self::KE2Message), ProtocolError> {
+        context: Vec<u8>,
+    ) -> Result<(Self::KE2State, Self::KE2Message), ProtocolError> {
         let server_e_kp = KeyPair::<G>::generate_random(rng);
         let server_nonce = generate_nonce::<R>(rng);
 
         let mut transcript_hasher = D::new()
-            .chain(STR_3DH)
-            .chain(&serialize(&id_u, 2)?)
+            .chain(STR_RFC)
+            .chain(serialize(&context, 2))
+            .chain(id_u)
             .chain(&serialized_credential_request[..])
-            .chain(&serialize(&id_s, 2)?)
+            .chain(id_s)
             .chain(&l2_bytes[..])
             .chain(&server_nonce[..])
-            .chain(&server_e_kp.public().to_arr());
+            .chain(server_e_kp.public().to_arr());
 
-        let (session_key, km2, ke2, km3) = derive_3dh_keys::<D, G>(
+        let (session_key, km2, km3) = derive_3dh_keys::<D, G>(
             TripleDHComponents {
                 pk1: ke1_message.client_e_pk.clone(),
                 sk1: server_e_kp.private().clone(),
@@ -108,28 +106,14 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
             &transcript_hasher.clone().finalize(),
         )?;
 
-        // Compute encryption of e_info
-        let h = Hkdf::<D>::from_prk(&ke2).map_err(|_| InternalPakeError::HkdfError)?;
-        let mut encryption_pad = vec![0u8; e_info.len()];
-        h.expand(STR_ENCRYPTION_PAD, &mut encryption_pad)
-            .map_err(|_| InternalPakeError::HkdfError)?;
-        let ciphertext: Vec<u8> = encryption_pad
-            .iter()
-            .zip(e_info.iter())
-            .map(|(&x1, &x2)| x1 ^ x2)
-            .collect();
-
-        transcript_hasher.update(&serialize(&ciphertext, 2)?);
-
         let mut mac_hasher =
-            Hmac::<D>::new_varkey(&km2).map_err(|_| InternalPakeError::HmacError)?;
+            Hmac::<D>::new_from_slice(&km2).map_err(|_| InternalPakeError::HmacError)?;
         mac_hasher.update(&transcript_hasher.clone().finalize());
         let mac = mac_hasher.finalize().into_bytes();
 
         transcript_hasher.update(&mac);
 
         Ok((
-            ke1_message.info,
             Ke2State {
                 km3,
                 hashed_transcript: transcript_hasher.finalize(),
@@ -138,7 +122,6 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
             Ke2Message {
                 server_nonce,
                 server_e_pk: server_e_kp.public().clone(),
-                e_info: ciphertext,
                 mac,
             },
         ))
@@ -150,20 +133,22 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
         ke2_message: Self::KE2Message,
         ke1_state: &Self::KE1State,
         serialized_credential_request: &[u8],
-        server_s_pk: Key,
-        client_s_sk: Key,
+        server_s_pk: PublicKey,
+        client_s_sk: PrivateKey,
         id_u: Vec<u8>,
         id_s: Vec<u8>,
-    ) -> Result<(Vec<u8>, Vec<u8>, Self::KE3Message), ProtocolError> {
+        context: Vec<u8>,
+    ) -> Result<(Vec<u8>, Self::KE3Message), ProtocolError> {
         let mut transcript_hasher = D::new()
-            .chain(STR_3DH)
-            .chain(&serialize(&id_u, 2)?)
-            .chain(&serialized_credential_request)
-            .chain(&serialize(&id_s, 2)?)
+            .chain(STR_RFC)
+            .chain(serialize(&context, 2))
+            .chain(id_u)
+            .chain(serialized_credential_request)
+            .chain(id_s)
             .chain(&l2_component[..])
-            .chain(&ke2_message.to_bytes_without_info_or_mac());
+            .chain(ke2_message.to_bytes_without_info_or_mac());
 
-        let (session_key, km2, ke2, km3) = derive_3dh_keys::<D, G>(
+        let (session_key, km2, km3) = derive_3dh_keys::<D, G>(
             TripleDHComponents {
                 pk1: ke2_message.server_e_pk.clone(),
                 sk1: ke1_state.client_e_sk.clone(),
@@ -175,10 +160,8 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
             &transcript_hasher.clone().finalize(),
         )?;
 
-        transcript_hasher.update(&serialize(&ke2_message.e_info[..], 2)?);
-
         let mut server_mac =
-            Hmac::<D>::new_varkey(&km2).map_err(|_| InternalPakeError::HmacError)?;
+            Hmac::<D>::new_from_slice(&km2).map_err(|_| InternalPakeError::HmacError)?;
         server_mac.update(&transcript_hasher.clone().finalize());
 
         if server_mac.verify(&ke2_message.mac).is_err() {
@@ -187,25 +170,13 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
             ));
         }
 
-        transcript_hasher.update(ke2_message.mac.to_vec());
+        transcript_hasher.update(ke2_message.mac);
 
         let mut client_mac =
-            Hmac::<D>::new_varkey(&km3).map_err(|_| InternalPakeError::HmacError)?;
+            Hmac::<D>::new_from_slice(&km3).map_err(|_| InternalPakeError::HmacError)?;
         client_mac.update(&transcript_hasher.finalize());
 
-        // Compute decryption of e_info
-        let h = Hkdf::<D>::from_prk(&ke2).map_err(|_| InternalPakeError::HkdfError)?;
-        let mut encryption_pad = vec![0u8; ke2_message.e_info.len()];
-        h.expand(STR_ENCRYPTION_PAD, &mut encryption_pad)
-            .map_err(|_| InternalPakeError::HkdfError)?;
-        let plaintext: Vec<u8> = encryption_pad
-            .iter()
-            .zip(ke2_message.e_info.iter())
-            .map(|(&x1, &x2)| x1 ^ x2)
-            .collect();
-
         Ok((
-            plaintext,
             session_key.to_vec(),
             Ke3Message {
                 mac: client_mac.finalize().into_bytes(),
@@ -219,7 +190,7 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
         ke2_state: &Self::KE2State,
     ) -> Result<Vec<u8>, ProtocolError> {
         let mut client_mac =
-            Hmac::<D>::new_varkey(&ke2_state.km3).map_err(|_| InternalPakeError::HmacError)?;
+            Hmac::<D>::new_from_slice(&ke2_state.km3).map_err(|_| InternalPakeError::HmacError)?;
         client_mac.update(&ke2_state.hashed_transcript);
 
         if client_mac.verify(&ke3_message.mac).is_err() {
@@ -237,30 +208,29 @@ impl<D: Hash, G: Group> KeyExchange<D, G> for TripleDH {
 }
 
 /// The client state produced after the first key exchange message
-#[derive(PartialEq, Eq, Zeroize)]
+#[derive(PartialEq, Eq, Debug, Hash, Zeroize, Clone)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
 #[zeroize(drop)]
 pub struct Ke1State {
-    client_e_sk: Key,
+    client_e_sk: PrivateKey,
     client_nonce: GenericArray<u8, NonceLen>,
 }
 
 /// The first key exchange message
-#[derive(PartialEq, Eq)]
+#[derive(PartialEq, Eq, Debug, Hash, Clone)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
 pub struct Ke1Message {
     pub(crate) client_nonce: GenericArray<u8, NonceLen>,
-    pub(crate) info: Vec<u8>,
-    pub(crate) client_e_pk: Key,
+    pub(crate) client_e_pk: PublicKey,
 }
 
-impl TryFrom<&[u8]> for Ke1State {
-    type Error = PakeError;
-
-    fn try_from(bytes: &[u8]) -> Result<Self, Self::Error> {
+impl FromBytes for Ke1State {
+    fn from_bytes<CS: CipherSuite>(bytes: &[u8]) -> Result<Self, PakeError> {
         let nonce_len = NonceLen::to_usize();
         let checked_bytes = check_slice_size_atleast(bytes, KEY_LEN + nonce_len, "ke1_state")?;
 
         Ok(Self {
-            client_e_sk: Key::from_bytes(&checked_bytes[..KEY_LEN])?,
+            client_e_sk: PrivateKey::from_bytes(&checked_bytes[..KEY_LEN])?,
             client_nonce: GenericArray::clone_from_slice(
                 &checked_bytes[KEY_LEN..KEY_LEN + nonce_len],
             ),
@@ -269,9 +239,9 @@ impl TryFrom<&[u8]> for Ke1State {
 }
 
 impl ToBytesWithPointers for Ke1State {
-    fn to_bytes(&self) -> Result<Vec<u8>, ProtocolError> {
+    fn to_bytes(&self) -> Vec<u8> {
         let output: Vec<u8> = [&self.client_e_sk.to_arr(), &self.client_nonce[..]].concat();
-        Ok(output)
+        output
     }
 
     #[cfg(test)]
@@ -279,7 +249,7 @@ impl ToBytesWithPointers for Ke1State {
         vec![
             (
                 self.client_e_sk.as_ptr(),
-                <Key as SizedBytes>::Len::to_usize(),
+                <PrivateKey as SizedBytes>::Len::to_usize(),
             ),
             (self.client_nonce.as_ptr(), NonceLen::to_usize()),
         ]
@@ -287,36 +257,27 @@ impl ToBytesWithPointers for Ke1State {
 }
 
 impl ToBytes for Ke1Message {
-    fn to_bytes(&self) -> Result<Vec<u8>, ProtocolError> {
-        Ok([
-            &self.client_nonce[..],
-            &serialize(&self.info, 2)?,
-            &self.client_e_pk.to_arr(),
-        ]
-        .concat())
+    fn to_bytes(&self) -> Vec<u8> {
+        [&self.client_nonce[..], &self.client_e_pk.to_arr()].concat()
     }
 }
 
-impl TryFrom<&[u8]> for Ke1Message {
-    type Error = PakeError;
-
-    fn try_from(ke1_message_bytes: &[u8]) -> Result<Self, Self::Error> {
+impl FromBytes for Ke1Message {
+    fn from_bytes<CS: CipherSuite>(ke1_message_bytes: &[u8]) -> Result<Self, PakeError> {
         let nonce_len = NonceLen::to_usize();
         let checked_nonce =
-            check_slice_size_atleast(ke1_message_bytes, nonce_len, "ke1_message nonce")?;
-
-        let (info, remainder) = tokenize(&checked_nonce[nonce_len..], 2)?;
-
-        let checked_client_e_pk = check_slice_size(&remainder, KEY_LEN, "ke1_message client_e_pk")?;
+            check_slice_size(ke1_message_bytes, nonce_len + KEY_LEN, "ke1_message nonce")?;
 
         Ok(Self {
             client_nonce: GenericArray::clone_from_slice(&checked_nonce[..nonce_len]),
-            info,
-            client_e_pk: Key::from_bytes(&checked_client_e_pk)?,
+            client_e_pk: PublicKey::from_bytes(&checked_nonce[nonce_len..])?,
         })
     }
 }
 /// The server state produced after the second key exchange message
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serialize", serde(bound = ""))]
 pub struct Ke2State<HashLen: ArrayLength<u8>> {
     km3: GenericArray<u8, HashLen>,
     hashed_transcript: GenericArray<u8, HashLen>,
@@ -339,13 +300,13 @@ impl<HashLen: ArrayLength<u8>> Drop for Ke2State<HashLen> {
 }
 
 impl<HashLen: ArrayLength<u8>> ToBytesWithPointers for Ke2State<HashLen> {
-    fn to_bytes(&self) -> Result<Vec<u8>, ProtocolError> {
-        Ok([
+    fn to_bytes(&self) -> Vec<u8> {
+        [
             &self.km3[..],
             &self.hashed_transcript[..],
             &self.session_key[..],
         ]
-        .concat())
+        .concat()
     }
 
     #[cfg(test)]
@@ -359,18 +320,17 @@ impl<HashLen: ArrayLength<u8>> ToBytesWithPointers for Ke2State<HashLen> {
 }
 
 /// The second key exchange message
-#[derive(Clone)]
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serialize", serde(bound = ""))]
 pub struct Ke2Message<HashLen: ArrayLength<u8>> {
     server_nonce: GenericArray<u8, NonceLen>,
-    server_e_pk: Key,
-    e_info: Vec<u8>,
+    server_e_pk: PublicKey,
     mac: GenericArray<u8, HashLen>,
 }
 
-impl<HashLen: ArrayLength<u8>> TryFrom<&[u8]> for Ke2State<HashLen> {
-    type Error = PakeError;
-
-    fn try_from(input: &[u8]) -> Result<Self, Self::Error> {
+impl<HashLen: ArrayLength<u8>> FromBytes for Ke2State<HashLen> {
+    fn from_bytes<CS: CipherSuite>(input: &[u8]) -> Result<Self, PakeError> {
         let hash_len = HashLen::to_usize();
         let checked_bytes = check_slice_size(input, 3 * hash_len, "ke2_state")?;
 
@@ -385,13 +345,8 @@ impl<HashLen: ArrayLength<u8>> TryFrom<&[u8]> for Ke2State<HashLen> {
 }
 
 impl<HashLen: ArrayLength<u8>> ToBytes for Ke2Message<HashLen> {
-    fn to_bytes(&self) -> Result<Vec<u8>, ProtocolError> {
-        Ok([
-            &self.to_bytes_without_info_or_mac(),
-            &serialize(&self.e_info, 2)?,
-            &self.mac[..],
-        ]
-        .concat())
+    fn to_bytes(&self) -> Vec<u8> {
+        [&self.to_bytes_without_info_or_mac(), &self.mac[..]].concat()
     }
 }
 
@@ -401,25 +356,31 @@ impl<HashLen: ArrayLength<u8>> Ke2Message<HashLen> {
     }
 }
 
-impl<HashLen: ArrayLength<u8>> TryFrom<&[u8]> for Ke2Message<HashLen> {
-    type Error = PakeError;
-
-    fn try_from(input: &[u8]) -> Result<Self, Self::Error> {
+impl<HashLen: ArrayLength<u8>> FromBytes for Ke2Message<HashLen> {
+    fn from_bytes<CS: CipherSuite>(input: &[u8]) -> Result<Self, PakeError> {
         let nonce_len = NonceLen::to_usize();
         let checked_nonce = check_slice_size_atleast(input, nonce_len, "ke2_message nonce")?;
-        let checked_server_e_pk = check_slice_size_atleast(
+
+        let unchecked_server_e_pk = check_slice_size_atleast(
             &checked_nonce[nonce_len..],
             KEY_LEN,
             "ke2_message server_e_pk",
         )?;
-        let (e_info, remainder) = tokenize(&checked_server_e_pk[KEY_LEN..], 2)?;
-        let checked_mac = check_slice_size(&remainder, HashLen::to_usize(), "ke1_message mac")?;
+        let checked_mac = check_slice_size(
+            &unchecked_server_e_pk[KEY_LEN..],
+            HashLen::to_usize(),
+            "ke1_message mac",
+        )?;
+
+        // Check the public key bytes
+        let server_e_pk = KeyPair::<CS::Group>::check_public_key(PublicKey::from_bytes(
+            &unchecked_server_e_pk[..KEY_LEN],
+        )?)?;
 
         Ok(Self {
             server_nonce: GenericArray::clone_from_slice(&checked_nonce[..nonce_len]),
-            server_e_pk: Key::from_bytes(&checked_server_e_pk[..KEY_LEN])?,
-            e_info,
-            mac: GenericArray::clone_from_slice(&checked_mac),
+            server_e_pk: PublicKey::from_bytes(&server_e_pk)?,
+            mac: GenericArray::clone_from_slice(checked_mac),
         })
     }
 }
@@ -427,42 +388,42 @@ impl<HashLen: ArrayLength<u8>> TryFrom<&[u8]> for Ke2Message<HashLen> {
 #[allow(clippy::upper_case_acronyms)]
 // The triple of public and private components used in the 3DH computation
 struct TripleDHComponents {
-    pk1: Key,
-    sk1: Key,
-    pk2: Key,
-    sk2: Key,
-    pk3: Key,
-    sk3: Key,
+    pk1: PublicKey,
+    sk1: PrivateKey,
+    pk2: PublicKey,
+    sk2: PrivateKey,
+    pk3: PublicKey,
+    sk3: PrivateKey,
 }
 
 #[allow(clippy::upper_case_acronyms)]
-// Consists of a session key, followed by two mac keys and an encryption key: (session_key, km2, ke2, km3)
+// Consists of a session key, followed by two mac keys: (session_key, km2, km3)
 type TripleDHDerivationResult<D> = (
     GenericArray<u8, <D as FixedOutput>::OutputSize>,
     GenericArray<u8, <D as FixedOutput>::OutputSize>,
     GenericArray<u8, <D as FixedOutput>::OutputSize>,
-    GenericArray<u8, <D as FixedOutput>::OutputSize>,
 );
 
 /// The third key exchange message
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serialize", serde(bound = ""))]
 pub struct Ke3Message<HashLen: ArrayLength<u8>> {
     mac: GenericArray<u8, HashLen>,
 }
 
 impl<HashLen: ArrayLength<u8>> ToBytes for Ke3Message<HashLen> {
-    fn to_bytes(&self) -> Result<Vec<u8>, ProtocolError> {
-        Ok(self.mac.to_vec())
+    fn to_bytes(&self) -> Vec<u8> {
+        self.mac.to_vec()
     }
 }
 
-impl<HashLen: ArrayLength<u8>> TryFrom<&[u8]> for Ke3Message<HashLen> {
-    type Error = PakeError;
-
-    fn try_from(bytes: &[u8]) -> Result<Self, Self::Error> {
-        let checked_bytes = check_slice_size(&bytes, HashLen::to_usize(), "ke3_message")?;
+impl<HashLen: ArrayLength<u8>> FromBytes for Ke3Message<HashLen> {
+    fn from_bytes<CS: CipherSuite>(bytes: &[u8]) -> Result<Self, PakeError> {
+        let checked_bytes = check_slice_size(bytes, HashLen::to_usize(), "ke3_message")?;
 
         Ok(Self {
-            mac: GenericArray::clone_from_slice(&checked_bytes),
+            mac: GenericArray::clone_from_slice(checked_bytes),
         })
     }
 }
@@ -485,30 +446,24 @@ fn derive_3dh_keys<D: Hash, G: Group>(
     let extracted_ikm = Hkdf::<D>::new(None, &ikm);
     let handshake_secret = derive_secrets::<D>(
         &extracted_ikm,
-        &STR_HANDSHAKE_SECRET,
-        &hashed_derivation_transcript,
+        STR_HANDSHAKE_SECRET,
+        hashed_derivation_transcript,
     )?;
     let session_key = derive_secrets::<D>(
         &extracted_ikm,
-        &STR_SESSION_SECRET,
-        &hashed_derivation_transcript,
+        STR_SESSION_KEY,
+        hashed_derivation_transcript,
     )?;
 
     let km2 = hkdf_expand_label::<D>(
         &handshake_secret,
-        &STR_SERVER_MAC,
-        b"",
-        <D as Digest>::OutputSize::to_usize(),
-    )?;
-    let ke2 = hkdf_expand_label::<D>(
-        &handshake_secret,
-        &STR_HANDSHAKE_ENC,
+        STR_SERVER_MAC,
         b"",
         <D as Digest>::OutputSize::to_usize(),
     )?;
     let km3 = hkdf_expand_label::<D>(
         &handshake_secret,
-        &STR_CLIENT_MAC,
+        STR_CLIENT_MAC,
         b"",
         <D as Digest>::OutputSize::to_usize(),
     )?;
@@ -516,7 +471,6 @@ fn derive_3dh_keys<D: Hash, G: Group>(
     Ok((
         GenericArray::clone_from_slice(&session_key),
         GenericArray::clone_from_slice(&km2),
-        GenericArray::clone_from_slice(&ke2),
         GenericArray::clone_from_slice(&km3),
     ))
 }
@@ -545,11 +499,11 @@ fn hkdf_expand_label_extracted<D: Hash>(
     hkdf_label.extend_from_slice(&length_u16.to_be_bytes());
 
     let mut opaque_label: Vec<u8> = Vec::new();
-    opaque_label.extend_from_slice(&STR_OPAQUE);
-    opaque_label.extend_from_slice(&label);
-    hkdf_label.extend_from_slice(&serialize(&opaque_label, 1)?);
+    opaque_label.extend_from_slice(STR_OPAQUE);
+    opaque_label.extend_from_slice(label);
+    hkdf_label.extend_from_slice(&serialize(&opaque_label, 1));
 
-    hkdf_label.extend_from_slice(&serialize(&context, 1)?);
+    hkdf_label.extend_from_slice(&serialize(context, 1));
 
     hkdf.expand(&hkdf_label, &mut okm)
         .map_err(|_| InternalPakeError::HkdfError)?;
@@ -564,7 +518,7 @@ fn derive_secrets<D: Hash>(
     hkdf_expand_label_extracted::<D>(
         hkdf,
         label,
-        &hashed_derivation_transcript,
+        hashed_derivation_transcript,
         <D as Digest>::OutputSize::to_usize(),
     )
 }

src/keypair.rs

@@ -35,13 +35,22 @@ pub trait SizedBytesExt: SizedBytes {
 impl<T> SizedBytesExt for T where T: SizedBytes {}
 
 /// A Keypair trait with public-private verification
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
 pub struct KeyPair<G> {
-    pk: Key,
-    sk: Key,
+    pk: PublicKey,
+    sk: PrivateKey,
     _g: PhantomData<G>,
 }
 
+impl_clone_for!(
+    struct KeyPair<G>,
+    [pk, sk, _g],
+);
+impl_debug_eq_hash_for!(
+    struct KeyPair<G>,
+    [pk, sk, _g],
+);
+
 // This can't be derived because of the use of a phantom parameter
 impl<G> Zeroize for KeyPair<G> {
     fn zeroize(&mut self) {
@@ -58,12 +67,12 @@ impl<G> Drop for KeyPair<G> {
 
 impl<G: Group> KeyPair<G> {
     /// The public key component
-    pub fn public(&self) -> &Key {
+    pub fn public(&self) -> &PublicKey {
         &self.pk
     }
 
     /// The private key component
-    pub fn private(&self) -> &Key {
+    pub fn private(&self) -> &PrivateKey {
         &self.sk
     }
 
@@ -71,40 +80,46 @@ impl<G: Group> KeyPair<G> {
     pub(crate) fn generate_random<R: RngCore + CryptoRng>(rng: &mut R) -> Self {
         let sk = G::random_nonzero_scalar(rng);
         let sk_bytes = G::scalar_as_bytes(&sk);
-        let pk = G::base_point().mult_by_slice(&sk_bytes);
+        let pk = G::base_point().mult_by_slice(sk_bytes);
         Self {
-            pk: Key(pk.to_arr().to_vec()),
-            sk: Key(sk_bytes.to_vec()),
+            pk: PublicKey(Key(pk.to_arr().to_vec())),
+            sk: PrivateKey(Key(sk_bytes.to_vec())),
             _g: PhantomData,
         }
     }
 
     /// Obtaining a public key from secret bytes. At all times, we should have
     /// &public_from_private(self.private()) == self.public()
-    pub(crate) fn public_from_private(bytes: &Key) -> Key {
+    pub(crate) fn public_from_private(bytes: &PrivateKey) -> PublicKey {
         let bytes_data = GenericArray::<u8, G::ScalarLen>::from_slice(&bytes.0[..]);
-        Key(G::base_point().mult_by_slice(&bytes_data).to_arr().to_vec())
+        PublicKey(Key(G::base_point()
+            .mult_by_slice(bytes_data)
+            .to_arr()
+            .to_vec()))
     }
 
     /// Check whether a public key is valid. This is meant to be applied on
     /// material provided through the network which fits the key
     /// representation (i.e. can be mapped to a curve point), but presents
     /// some risk - e.g. small subgroup check
-    pub(crate) fn check_public_key(key: Key) -> Result<Key, InternalPakeError> {
+    pub(crate) fn check_public_key(key: PublicKey) -> Result<PublicKey, InternalPakeError> {
         G::from_element_slice(GenericArray::from_slice(&key.0)).map(|_| key)
     }
 
     /// Computes the diffie hellman function on a public key and private key
-    pub(crate) fn diffie_hellman(pk: Key, sk: Key) -> Result<Vec<u8>, InternalPakeError> {
+    pub(crate) fn diffie_hellman(
+        pk: PublicKey,
+        sk: PrivateKey,
+    ) -> Result<Vec<u8>, InternalPakeError> {
         let pk_data = GenericArray::<u8, G::ElemLen>::from_slice(&pk.0[..]);
-        let point = G::from_element_slice(&pk_data)?;
+        let point = G::from_element_slice(pk_data)?;
         let secret_data = GenericArray::<u8, G::ScalarLen>::from_slice(&sk.0[..]);
-        Ok(G::mult_by_slice(&point, &secret_data).to_arr().to_vec())
+        Ok(G::mult_by_slice(&point, secret_data).to_arr().to_vec())
     }
 
     /// Obtains a KeyPair from a slice representing the private key
     pub fn from_private_key_slice(input: &[u8]) -> Result<Self, InternalPakeError> {
-        let sk = Key::from_arr(GenericArray::from_slice(&input))?;
+        let sk = PrivateKey(Key::from_arr(GenericArray::from_slice(input))?);
         let pk = Self::public_from_private(&sk);
         Ok(Self {
             pk,
@@ -116,8 +131,8 @@ impl<G: Group> KeyPair<G> {
     #[cfg(test)]
     pub fn as_byte_ptrs(&self) -> Vec<(*const u8, usize)> {
         vec![
-            (self.pk.as_ptr(), <Key as SizedBytes>::Len::to_usize()),
-            (self.sk.as_ptr(), <Key as SizedBytes>::Len::to_usize()),
+            (self.pk.as_ptr(), KeyLen::to_usize()),
+            (self.sk.as_ptr(), KeyLen::to_usize()),
         ]
     }
 }
@@ -129,18 +144,21 @@ impl<G: Group + Debug> KeyPair<G> {
     fn uniform_keypair_strategy() -> BoxedStrategy<Self> {
         // The no_shrink is because keypairs should be fixed -- shrinking would cause a different
         // keypair to be generated, which appears to not be very useful.
-        any::<[u8; 32]>()
-            .prop_filter_map("valid random keypair", |seed| {
+        prop::array::uniform32(0_u8..)
+            .prop_map(|seed| {
                 let mut rng = StdRng::from_seed(seed);
-                Some(Self::generate_random(&mut rng))
+                Self::generate_random(&mut rng)
             })
             .no_shrink()
             .boxed()
     }
 }
 
+type KeyLen = U32;
+
 /// A minimalist key type built around a \[u8; 32\]
-#[derive(Debug, PartialEq, Eq, Clone, Zeroize)]
+#[derive(Debug, PartialEq, Eq, Clone, Hash, Zeroize)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
 // Ensure Key material is zeroed after use.
 #[zeroize(drop)]
 #[repr(transparent)]
@@ -154,18 +172,74 @@ impl Deref for Key {
     }
 }
 
-impl SizedBytes for Key {
-    type Len = U32;
-
-    fn to_arr(&self) -> GenericArray<u8, Self::Len> {
+// Don't make it implement SizedBytes so that it's not constructible outside of this module.
+impl Key {
+    fn to_arr(&self) -> GenericArray<u8, KeyLen> {
         GenericArray::clone_from_slice(&self.0[..])
     }
 
-    fn from_arr(key_bytes: &GenericArray<u8, Self::Len>) -> Result<Self, TryFromSizedBytesError> {
+    #[allow(clippy::unnecessary_wraps)]
+    fn from_arr(key_bytes: &GenericArray<u8, KeyLen>) -> Result<Self, TryFromSizedBytesError> {
         Ok(Key(key_bytes.to_vec()))
     }
 }
 
+/// Wrapper around a Key to enforce that it's a private one.
+#[derive(Debug, PartialEq, Eq, Clone, Hash, Zeroize)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
+// Ensure Key material is zeroed after use.
+#[zeroize(drop)]
+#[repr(transparent)]
+pub struct PrivateKey(Key);
+
+impl Deref for PrivateKey {
+    type Target = Key;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl SizedBytes for PrivateKey {
+    type Len = KeyLen;
+
+    fn to_arr(&self) -> GenericArray<u8, Self::Len> {
+        self.0.to_arr()
+    }
+
+    fn from_arr(key_bytes: &GenericArray<u8, Self::Len>) -> Result<Self, TryFromSizedBytesError> {
+        Ok(PrivateKey(Key::from_arr(key_bytes)?))
+    }
+}
+
+/// Wrapper around a Key to enforce that it's a public one.
+#[derive(Debug, PartialEq, Eq, Clone, Hash, Zeroize)]
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
+// Ensure Key material is zeroed after use.
+#[zeroize(drop)]
+#[repr(transparent)]
+pub struct PublicKey(Key);
+
+impl Deref for PublicKey {
+    type Target = Key;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl SizedBytes for PublicKey {
+    type Len = KeyLen;
+
+    fn to_arr(&self) -> GenericArray<u8, Self::Len> {
+        self.0.to_arr()
+    }
+
+    fn from_arr(key_bytes: &GenericArray<u8, Self::Len>) -> Result<Self, TryFromSizedBytesError> {
+        Ok(PublicKey(Key::from_arr(key_bytes)?))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -177,7 +251,7 @@ mod tests {
 
     #[test]
     fn test_zeroize_key() -> Result<(), ProtocolError> {
-        let key_len = <Key as SizedBytes>::Len::to_usize();
+        let key_len = KeyLen::to_usize();
         let mut key = Key(vec![1u8; key_len]);
         let ptr = key.as_ptr();
 
@@ -207,21 +281,21 @@ mod tests {
 
     proptest! {
         #[test]
-        fn test_ristretto_check(kp in KeyPair::<RistrettoPoint>::uniform_keypair_strategy()) {
+        fn test_ristretto_check(ref kp in KeyPair::<RistrettoPoint>::uniform_keypair_strategy()) {
             let pk = kp.public();
             prop_assert!(KeyPair::<RistrettoPoint>::check_public_key(pk.clone()).is_ok());
         }
 
         #[test]
-        fn test_ristretto_pub_from_priv(kp in KeyPair::<RistrettoPoint>::uniform_keypair_strategy()) {
+        fn test_ristretto_pub_from_priv(ref kp in KeyPair::<RistrettoPoint>::uniform_keypair_strategy()) {
             let pk = kp.public();
             let sk = kp.private();
             prop_assert_eq!(&KeyPair::<RistrettoPoint>::public_from_private(sk), pk);
         }
 
         #[test]
-        fn test_ristretto_dh(kp1 in KeyPair::<RistrettoPoint>::uniform_keypair_strategy(),
-                          kp2 in KeyPair::<RistrettoPoint>::uniform_keypair_strategy()) {
+        fn test_ristretto_dh(ref kp1 in KeyPair::<RistrettoPoint>::uniform_keypair_strategy(),
+        ref kp2 in KeyPair::<RistrettoPoint>::uniform_keypair_strategy()) {
 
             let dh1 = KeyPair::<RistrettoPoint>::diffie_hellman(kp1.public().clone(), kp2.private().clone())?;
             let dh2 = KeyPair::<RistrettoPoint>::diffie_hellman(kp2.public().clone(), kp1.private().clone())?;
@@ -230,7 +304,7 @@ mod tests {
         }
 
         #[test]
-        fn test_private_key_slice(kp in KeyPair::<RistrettoPoint>::uniform_keypair_strategy()) {
+        fn test_private_key_slice(ref kp in KeyPair::<RistrettoPoint>::uniform_keypair_strategy()) {
             let sk_bytes = kp.private().to_vec();
 
             let kp2 = KeyPair::<RistrettoPoint>::from_private_key_slice(&sk_bytes)?;

src/lib.rs

@@ -5,7 +5,7 @@
 
 //! An implementation of the OPAQUE asymmetric password authentication key exchange protocol
 //!
-//! Note: This implementation is in sync with [draft-irtf-cfrg-opaque-03](https://www.ietf.org/archive/id/draft-irtf-cfrg-opaque-03.html),
+//! Note: This implementation is in sync with [draft-irtf-cfrg-opaque-05](https://www.ietf.org/archive/id/draft-irtf-cfrg-opaque-05.html),
 //! but this specification is subject to change, until the final version published by the IETF.
 //!
 //! # Overview
@@ -19,7 +19,7 @@
 //!
 //! We will use the following choices in this example:
 //! ```
-//! use opaque_ke::ciphersuite::CipherSuite;
+//! use opaque_ke::CipherSuite;
 //! struct Default;
 //! impl CipherSuite for Default {
 //!     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -32,14 +32,15 @@
 //! for a working example of a simple password-based login using OPAQUE.
 //!
 //! Note that our choice of slow hashing function in this example, `NoOpHash`, is selected only to ensure
-//! that the tests execute quickly. A real application should use an actual slow hashing function, such as `scrypt`,
-//! which can be enabled through the `slow-hash` feature.
+//! that the tests execute quickly. A real application should use an actual slow hashing function, such as `Argon2`,
+//! which can be enabled through the `slow-hash` feature. See more details in the [features](#features) section.
 //!
 //! ## Setup
-//! To set up the protocol, the server begins by generating a static keypair:
+//! To set up the protocol, the server begins by creating a `ServerSetup` object:
 //! ```
 //! # use opaque_ke::errors::ProtocolError;
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
+//! # use opaque_ke::ServerSetup;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -49,17 +50,17 @@
 //! # }
 //! use rand::{rngs::OsRng, RngCore};
 //! let mut rng = OsRng;
-//! let server_kp = Default::generate_random_keypair(&mut rng);
+//! let server_setup = ServerSetup::<Default>::new(&mut rng);
 //! # Ok::<(), ProtocolError>(())
 //! ```
-//! The server must persist this keypair for the registration and login steps, where the public component will be
-//! used by the client during both registration and login, and the private component will be used by the server during login.
+//! The server must persist an instance of [ServerSetup] for the registration and login steps.
 //!
 //! ## Registration
 //! The registration protocol between the client and server consists of four steps along with three messages:
 //! [RegistrationRequest], [RegistrationResponse], and [RegistrationUpload]. A successful execution of the registration protocol results in the
-//! server producing a password file corresponding to the password provided by
-//! the client. This password file is typically stored server-side, and retrieved upon future login attempts made by the client.
+//! server producing a password file corresponding to a server-side identifier for the client, along with the password provided by
+//! the client. This password file is typically stored in a key-value database, where the keys consist of these server-side identifiers for each client,
+//! and the values consist of their corresponding password files, to be retrieved upon future login attempts made by the client.
 //!
 //! ### Client Registration Start
 //! In the first step of registration, the client chooses as input a registration password. The client runs [ClientRegistration::start]
@@ -71,7 +72,7 @@
 //! #   ServerRegistration,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -90,18 +91,18 @@
 //! ```
 //!
 //! ### Server Registration Start
-//! In the second step of registration, the server takes as input the instance of [RegistrationRequest] from the client, and
-//! the server's public key `server_kp.public()`.
-//! The server runs [ServerRegistration::start] to produce an a [ServerRegistrationStartResult], which consists of
-//! a [RegistrationResponse] to be returned to the client and
-//! a [ServerRegistration] which must be persisted on the server for the final step of server registration.
+//! In the second step of registration, the server takes as input a persisted instance of [ServerSetup], a [RegistrationRequest] from the client, and
+//! a server-side identifier for the client.
+//! The server runs [ServerRegistration::start] to produce a [ServerRegistrationStartResult], which consists of
+//! a [RegistrationResponse] to be returned to the client.
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
 //! #   ClientRegistration,
+//! #   ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -116,12 +117,12 @@
 //! #     b"password",
 //! # )?;
 //! use opaque_ke::ServerRegistration;
-//! let mut server_rng = OsRng;
-//! let server_kp = Default::generate_random_keypair(&mut server_rng);
+//! # let mut server_rng = OsRng;
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
 //! let server_registration_start_result = ServerRegistration::<Default>::start(
-//!     &mut server_rng,
+//!     &server_setup,
 //!     client_registration_start_result.message,
-//!     server_kp.public(),
+//!     b"[email protected]",
 //! )?;
 //! # Ok::<(), ProtocolError>(())
 //! ```
@@ -135,10 +136,10 @@
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -153,8 +154,8 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
 //! let client_registration_finish_result = client_registration_start_result.state.finish(
 //!     &mut client_rng,
 //!     server_registration_start_result.message,
@@ -173,10 +174,10 @@
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -191,19 +192,20 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
 //! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::default())?;
-//! let password_file = server_registration_start_result.state.finish(
+//! let password_file = ServerRegistration::<Default>::finish(
 //!     client_registration_finish_result.message,
-//! )?;
+//! );
 //! # Ok::<(), ProtocolError>(())
 //! ```
 //!
 //! ## Login
 //! The login protocol between a client and server also consists of four steps along with three messages:
 //! [CredentialRequest], [CredentialResponse], [CredentialFinalization]. The server is expected to have access to the password file
-//! corresponding to an output of the registration phase. The login protocol will execute successfully only if the same password
+//! corresponding to an output of the registration phase (see [Dummy Server Login](#dummy-server-login) for handling the scenario where
+//! no password file is available). The login protocol will execute successfully only if the same password
 //! was used in the registration phase that produced the password file that the server is testing against.
 //!
 //! ### Client Login Start
@@ -217,7 +219,7 @@
 //! #   ClientRegistration, ServerRegistration, ServerLogin, CredentialFinalization,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -226,31 +228,31 @@
 //! #     type SlowHash = opaque_ke::slow_hash::NoOpHash;
 //! # }
 //! # use rand::{rngs::OsRng, RngCore};
-//! use opaque_ke::{ClientLogin, ClientLoginStartParameters};
+//! use opaque_ke::ClientLogin;
 //! let mut client_rng = OsRng;
 //! let client_login_start_result = ClientLogin::<Default>::start(
 //!   &mut client_rng,
 //!   b"password",
-//!   ClientLoginStartParameters::default(),
 //! )?;
 //! # Ok::<(), ProtocolError>(())
 //! ```
 //!
 //! ### Server Login Start
 //! In the second step of login, the server takes as input
-//! a [CredentialRequest] from the client,
-//! the server's private key `server_kp.private()`, and
-//! the password file output from registration.
+//! a persisted instance of [ServerSetup],
+//! the password file output from registration,
+//! a [CredentialRequest] from the client, and
+//! a server-side identifier for the client.
 //! The server runs [ServerLogin::start] to produce an output consisting of
 //! a [CredentialResponse] which is returned to the client, and
 //! a [ServerLogin] which must be persisted on the server for the final step of login.
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginStartParameters, CredentialFinalization,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, CredentialFinalization, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -265,27 +267,32 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
 //! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::default())?;
-//! # let password_file_bytes = server_registration_start_result.state.finish(client_registration_finish_result.message)?.serialize();
+//! # let password_file_bytes = ServerRegistration::<Default>::finish(client_registration_finish_result.message).serialize();
 //! # let client_login_start_result = ClientLogin::<Default>::start(
 //! #   &mut client_rng,
 //! #   b"password",
-//! #   ClientLoginStartParameters::default(),
 //! # )?;
 //! use opaque_ke::{ServerLogin, ServerLoginStartParameters};
 //! let password_file = ServerRegistration::<Default>::deserialize(&password_file_bytes[..])?;
 //! let mut server_rng = OsRng;
 //! let server_login_start_result = ServerLogin::start(
 //!     &mut server_rng,
-//!     password_file,
-//!     &server_kp.private(),
+//!     &server_setup,
+//!     Some(password_file),
 //!     client_login_start_result.message,
+//!     b"[email protected]",
 //!     ServerLoginStartParameters::default(),
 //! )?;
 //! # Ok::<(), ProtocolError>(())
 //! ```
+//! Note that if there is no corresponding password file found for the user,
+//! the server can use `None` in place of `Some(password_file)` in order to generate
+//! a [CredentialResponse] that is indistinguishable from a valid [CredentialResponse]
+//! returned for a registered client. This allows the server to prevent leaking information
+//! about whether or not a client has previously registered with the server.
 //!
 //! ### Client Login Finish
 //! In the third step of login, the client takes as input a [CredentialResponse] from the server.
@@ -295,10 +302,10 @@
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginStartParameters, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -313,21 +320,20 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
 //! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::default())?;
-//! # let password_file_bytes = server_registration_start_result.state.finish(client_registration_finish_result.message)?.serialize();
+//! # let password_file_bytes = ServerRegistration::<Default>::finish(client_registration_finish_result.message).serialize();
 //! # let client_login_start_result = ClientLogin::<Default>::start(
 //! #     &mut client_rng,
 //! #     b"password",
-//! #     ClientLoginStartParameters::default(),
 //! # )?;
 //! # let password_file =
 //! #   ServerRegistration::<Default>::deserialize(
 //! #     &password_file_bytes[..],
 //! #   )?;
 //! # let server_login_start_result =
-//! #     ServerLogin::start(&mut server_rng, password_file, &server_kp.private(), client_login_start_result.message, ServerLoginStartParameters::default())?;
+//! #     ServerLogin::start(&mut server_rng, &server_setup, Some(password_file), client_login_start_result.message, b"[email protected]", ServerLoginStartParameters::default())?;
 //! let client_login_finish_result = client_login_start_result.state.finish(
 //!     server_login_start_result.message,
 //!     ClientLoginFinishParameters::default(),
@@ -341,10 +347,10 @@
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginStartParameters, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -359,21 +365,20 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
 //! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::default())?;
-//! # let password_file_bytes = server_registration_start_result.state.finish(client_registration_finish_result.message)?.serialize();
+//! # let password_file_bytes = ServerRegistration::<Default>::finish(client_registration_finish_result.message).serialize();
 //! # let client_login_start_result = ClientLogin::<Default>::start(
 //! #   &mut client_rng,
 //! #   b"password",
-//! #   ClientLoginStartParameters::default(),
 //! # )?;
 //! # let password_file =
 //! #   ServerRegistration::<Default>::deserialize(
 //! #     &password_file_bytes[..],
 //! #   )?;
 //! # let server_login_start_result =
-//! #     ServerLogin::start(&mut server_rng, password_file, &server_kp.private(), client_login_start_result.message, ServerLoginStartParameters::default())?;
+//! #     ServerLogin::start(&mut server_rng, &server_setup, Some(password_file), client_login_start_result.message, b"[email protected]", ServerLoginStartParameters::default())?;
 //! # let client_login_finish_result = client_login_start_result.state.finish(
 //! #   server_login_start_result.message,
 //! #   ClientLoginFinishParameters::default(),
@@ -412,14 +417,15 @@
 //!
 //! A [ClientLoginFinishResult] contains the `server_s_pk` field, which is represents the static public key of the server that is established
 //! during the setup phase. This can be used by the client to verify the authenticity of the server it engages with during the login phase. In particular,
-//! the client can check that the static public key of the server supplied during registration matches this field during login.
+//! the client can check that the static public key of the server supplied during registration (with the `server_s_pk` field of
+//! [ClientRegistrationFinishResult]) matches this field during login.
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginStartParameters, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -434,25 +440,26 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! // During setup, server generates its static keypair
-//! let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
-//!
-//! // During setup or registration, the server transmits its static public key to the client
-//! let server_s_pk = server_kp.public(); // obtained from the server
-//! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::default())?;
-//! # let password_file_bytes = server_registration_start_result.state.finish(client_registration_finish_result.message)?.serialize();
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
+//! // During registration, the client obtains a ClientRegistrationFinishResult with
+//! // a server_s_pk field
+//! let client_registration_finish_result = client_registration_start_result.state.finish(
+//!     &mut client_rng,
+//!     server_registration_start_result.message,
+//!     ClientRegistrationFinishParameters::default(),
+//! )?;
+//! # let password_file_bytes = ServerRegistration::<Default>::finish(client_registration_finish_result.message).serialize();
 //! # let client_login_start_result = ClientLogin::<Default>::start(
 //! #     &mut client_rng,
 //! #     b"password",
-//! #     ClientLoginStartParameters::default(),
 //! # )?;
 //! # let password_file =
 //! #   ServerRegistration::<Default>::deserialize(
 //! #     &password_file_bytes[..],
 //! #   )?;
 //! # let server_login_start_result =
-//! #     ServerLogin::start(&mut server_rng, password_file, &server_kp.private(), client_login_start_result.message, ServerLoginStartParameters::default())?;
+//! #     ServerLogin::start(&mut server_rng, &server_setup, Some(password_file), client_login_start_result.message, b"[email protected]", ServerLoginStartParameters::default())?;
 //!
 //! // And then later, during login...
 //! let client_login_finish_result = client_login_start_result.state.finish(
@@ -460,11 +467,11 @@
 //!     ClientLoginFinishParameters::default(),
 //! )?;
 //!
-//! // Check that the server's static public key matches what was obtained during
-//! // setup or registration
+//! // Check that the server's static public key obtained from login matches what
+//! // was obtained during registration
 //! assert_eq!(
+//!     &client_registration_finish_result.server_s_pk,
 //!     &client_login_finish_result.server_s_pk,
-//!     server_s_pk,
 //! );
 //! # Ok::<(), ProtocolError>(())
 //! ```
@@ -492,10 +499,10 @@
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginStartParameters, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -510,26 +517,25 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
 //! // During registration...
 //! let client_registration_finish_result = client_registration_start_result.state.finish(
 //!     &mut client_rng,
 //!     server_registration_start_result.message,
 //!     ClientRegistrationFinishParameters::default()
 //! )?;
-//! # let password_file_bytes = server_registration_start_result.state.finish(client_registration_finish_result.message)?.serialize();
+//! # let password_file_bytes = ServerRegistration::<Default>::finish(client_registration_finish_result.message).serialize();
 //! # let client_login_start_result = ClientLogin::<Default>::start(
 //! #     &mut client_rng,
 //! #     b"password",
-//! #     ClientLoginStartParameters::default(),
 //! # )?;
 //! # let password_file =
 //! #   ServerRegistration::<Default>::deserialize(
 //! #     &password_file_bytes[..],
 //! #   )?;
 //! # let server_login_start_result =
-//! #     ServerLogin::start(&mut server_rng, password_file, &server_kp.private(), client_login_start_result.message, ServerLoginStartParameters::default())?;
+//! #     ServerLogin::start(&mut server_rng, &server_setup, Some(password_file), client_login_start_result.message, b"[email protected]", ServerLoginStartParameters::default())?;
 //!
 //! // And then later, during login...
 //! let client_login_finish_result = client_login_start_result.state.finish(
@@ -546,8 +552,10 @@
 //!
 //! ## Custom Identifiers
 //!
-//! Typically when applications use OPAQUE to authenticate a client to a server, the client has a registered "username" which is sent to the server to
-//! identify the corresponding password file established during registration. The server may also have an identifier corresponding to an entity (e.g. facebook.com).
+//! Typically when applications use OPAQUE to authenticate a client to a server, the client has a registered username which is sent to the server to
+//! identify the corresponding password file established during registration. This username may or may not coincide with the server-side identifier;
+//! however, this username must be known to both the client and the server (whereas the server-side identifier does not need to be exposed to the client).
+//! The server may also have an identifier corresponding to an entity (e.g. Facebook).
 //! By default, neither of these public identifiers need to be supplied to the OPAQUE protocol.
 //!
 //! But, for applications that wish to cryptographically bind these identities to
@@ -556,10 +564,10 @@
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, Identifiers, ServerRegistration, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -574,14 +582,16 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
 //! let client_registration_finish_result = client_registration_start_result.state.finish(
 //!     &mut client_rng,
 //!     server_registration_start_result.message,
 //!     ClientRegistrationFinishParameters::WithIdentifiers(
-//!         b"username".to_vec(),
-//!         b"facebook.com".to_vec(),
+//!         Identifiers::ClientAndServerIdentifiers(
+//!             b"Alice_the_Cryptographer".to_vec(),
+//!             b"Facebook".to_vec(),
+//!         ),
 //!     ),
 //! )?;
 //! # Ok::<(), ProtocolError>(())
@@ -591,10 +601,10 @@
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginStartParameters, CredentialFinalization,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, CredentialFinalization, Identifiers, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -609,26 +619,28 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
-//! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::WithIdentifiers(b"username".to_vec(), b"facebook.com".to_vec()))?;
-//! # let password_file_bytes = server_registration_start_result.state.finish(client_registration_finish_result.message)?.serialize();
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
+//! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::WithIdentifiers(Identifiers::ClientAndServerIdentifiers(b"Alice_the_Cryptographer".to_vec(), b"Facebook".to_vec())))?;
+//! # let password_file_bytes = ServerRegistration::<Default>::finish(client_registration_finish_result.message).serialize();
 //! # let client_login_start_result = ClientLogin::<Default>::start(
 //! #   &mut client_rng,
 //! #   b"password",
-//! #   ClientLoginStartParameters::default(),
 //! # )?;
 //! # use opaque_ke::{ServerLogin, ServerLoginStartParameters};
 //! # let password_file = ServerRegistration::<Default>::deserialize(&password_file_bytes[..])?;
 //! # let mut server_rng = OsRng;
 //! let server_login_start_result = ServerLogin::start(
 //!     &mut server_rng,
-//!     password_file,
-//!     &server_kp.private(),
+//!     &server_setup,
+//!     Some(password_file),
 //!     client_login_start_result.message,
+//!     b"[email protected]",
 //!     ServerLoginStartParameters::WithIdentifiers(
-//!         b"username".to_vec(),
-//!         b"facebook.com".to_vec(),
+//!         Identifiers::ClientAndServerIdentifiers(
+//!             b"Alice_the_Cryptographer".to_vec(),
+//!             b"Facebook".to_vec(),
+//!         ),
 //!     ),
 //! )?;
 //! # Ok::<(), ProtocolError>(())
@@ -638,10 +650,10 @@
 //! ```
 //! # use opaque_ke::{
 //! #   errors::ProtocolError,
-//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginStartParameters, ClientLoginFinishParameters, ServerLogin, ServerLoginStartParameters, CredentialFinalization,
+//! #   ClientRegistration, ClientRegistrationFinishParameters, ServerRegistration, ClientLogin, ClientLoginFinishParameters, Identifiers, ServerLogin, ServerLoginStartParameters, CredentialFinalization, ServerSetup,
 //! #   slow_hash::NoOpHash,
 //! # };
-//! # use opaque_ke::ciphersuite::CipherSuite;
+//! # use opaque_ke::CipherSuite;
 //! # struct Default;
 //! # impl CipherSuite for Default {
 //! #     type Group = curve25519_dalek::ristretto::RistrettoPoint;
@@ -656,48 +668,74 @@
 //! #     b"password",
 //! # )?;
 //! # let mut server_rng = OsRng;
-//! # let server_kp = Default::generate_random_keypair(&mut server_rng);
-//! # let server_registration_start_result = ServerRegistration::<Default>::start(&mut server_rng, client_registration_start_result.message, server_kp.public())?;
-//! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::WithIdentifiers(b"username".to_vec(), b"facebook.com".to_vec()))?;
-//! # let password_file_bytes = server_registration_start_result.state.finish(client_registration_finish_result.message)?.serialize();
+//! # let server_setup = ServerSetup::<Default>::new(&mut server_rng);
+//! # let server_registration_start_result = ServerRegistration::<Default>::start(&server_setup, client_registration_start_result.message, b"[email protected]")?;
+//! # let client_registration_finish_result = client_registration_start_result.state.finish(&mut client_rng, server_registration_start_result.message, ClientRegistrationFinishParameters::WithIdentifiers(Identifiers::ClientAndServerIdentifiers(b"Alice_the_Cryptographer".to_vec(), b"Facebook".to_vec())))?;
+//! # let password_file_bytes = ServerRegistration::<Default>::finish(client_registration_finish_result.message).serialize();
 //! # let client_login_start_result = ClientLogin::<Default>::start(
 //! #     &mut client_rng,
 //! #     b"password",
-//! #     ClientLoginStartParameters::default(),
 //! # )?;
 //! # let password_file =
 //! #   ServerRegistration::<Default>::deserialize(
 //! #     &password_file_bytes[..],
 //! #   )?;
 //! # let server_login_start_result =
-//! #     ServerLogin::start(&mut server_rng, password_file, &server_kp.private(), client_login_start_result.message, ServerLoginStartParameters::WithIdentifiers(b"username".to_vec(), b"facebook.com".to_vec()))?;
+//! #     ServerLogin::start(&mut server_rng, &server_setup, Some(password_file), client_login_start_result.message, b"[email protected]", ServerLoginStartParameters::WithIdentifiers(Identifiers::ClientAndServerIdentifiers(b"Alice_the_Cryptographer".to_vec(), b"Facebook".to_vec())))?;
 //! let client_login_finish_result = client_login_start_result.state.finish(
 //!     server_login_start_result.message,
 //!     ClientLoginFinishParameters::WithIdentifiers(
-//!         b"username".to_vec(),
-//!         b"facebook.com".to_vec(),
+//!         Identifiers::ClientAndServerIdentifiers(
+//!             b"Alice_the_Cryptographer".to_vec(),
+//!             b"Facebook".to_vec(),
+//!         ),
 //!     ),
 //! )?;
+//!
 //! # Ok::<(), ProtocolError>(())
 //! ```
 //! Failing to supply the same pair of custom identifiers in any of the three steps above will result in an error in attempting to complete
 //! the protocol!
 //!
-//! ## Key Exchange Additional Data
+//! Note that if only one of the client and server identifiers are present, then [Identifiers::ClientIdentifier] and [Identifiers::ServerIdentifier] can be
+//! used to specify them individually.
 //!
-//! A key exchange protocol typically supports the passing of data between the two parties before the exchange is complete, so as to bind the integrity
-//! and/or confidentiality of application-specific data to the security of the key exchange. During the login phase, the client and server can pass
-//! additional data alongside the first two messages of the protocol, with confidential data being supported for the second message.
+//! ## Key Exchange Context
 //!
-//! The following three messages support passing of additional data:
-//! - The first login message, where the client can populate [ClientLoginStartParameters::WithInfo] with plaintext additional data, and
-//! the server can retrieve using the `plain_info` field of [ServerLoginStartResult].
-//! - The second login message, where the server can populate [ServerLoginStartParameters::WithInfo] with confidential additional data,
-//! and the client can retrieve using the `confidential_info` field of [ClientLoginFinishResult].
+//! A key exchange protocol typically allows for the specifying of shared "context" information between the two parties before the exchange is complete,
+//! so as to bind the integrity of application-specific data or configuration parameters to the security of the key exchange.
+//! During the login phase, the client and server can specify this context using:
+//! - The second login message, where the server can populate [ServerLoginStartParameters::WithContext], and
+//! - The third login message, where the client can populate [ClientLoginFinishParameters::WithContext].
 //!
-//! For the second login message, the `WithInfoAndIdentifiers` variant can be used to specify these fields in addition to
-//! [custom identifiers](#custom-identifiers), with the ordering of the fields as `WithInfoAndIdentifiers(confidential_info, username, server_name)`.
+//! For both of these messages, the `WithContextAndIdentifiers` variant can be used to specify these fields in addition to
+//! [custom identifiers](#custom-identifiers), with the ordering of the fields as
+//! `WithContextAndIdentifiers(context, Identifiers::ClientAndServerIdentifiers(username, server_name))`.
 //!
+//! ## Dummy Server Login
+//!
+//! For applications in which the server does not wish to reveal to the client whether an existing password file has been
+//! registered, the server can return a "dummy" credential response message to the client for an unregistered client,
+//! which is indistinguishable from the normal credential response message that the server would return for a registered client.
+//! The dummy message is created by passing a `None` to the password_file parameter for [ServerLogin::start].
+//!
+//! # Features
+//!
+//! - The `slow-hash` feature, when enabled, introduces a dependency on `argon2` and implements the `SlowHash` trait for `Argon2`
+//! with a set of default parameters. In general, secure instantiations should choose to invoke a memory-hard password
+//! hashing function when the client's password is expected to have low entropy, instead of relying on [slow_hash::NoOpHash]
+//! as done in the above example. The more computationally intensive the `SlowHash` function is, the more resistant the server's
+//! password file records will be against offline dictionary and precomputation attacks; see
+//! [the OPAQUE paper](https://eprint.iacr.org/2018/163.pdf) for more details.
+//!
+//! - The `serialize` feature, enabled by default, provides convenience functions for serializing and deserializing with
+//! [serde](https://serde.rs/).
+//!
+//! - The `u32_backend` and `u64_backend` features are re-exported from
+//! [curve25519-dalek](https://doc.dalek.rs/curve25519_dalek/index.html#backends-and-features) and allow for selecting
+//! the corresponding backend for the curve arithmetic used. The `u64_backend` feature is included as the default.
+//!
+//! - The `bench` feature is used only for running performance benchmarks for this implementation.
 //!
 
 #![cfg_attr(not(feature = "bench"), deny(missing_docs))]
@@ -709,9 +747,18 @@ compile_error!(
      please enable one of: u64_backend, u32_backend"
 );
 
+#[cfg(test)]
+#[macro_use]
+extern crate proptest;
+
 // Error types
 pub mod errors;
 
+#[macro_use]
+mod impls;
+#[macro_use]
+mod serialization;
+
 // High-level API
 mod opaque;
 
@@ -735,8 +782,6 @@ mod oprf;
 
 pub mod slow_hash;
 
-mod serialization;
-
 #[cfg(test)]
 mod tests;
 
@@ -744,17 +789,20 @@ mod tests;
 
 pub use rand;
 
+pub use ciphersuite::CipherSuite;
+
 pub use crate::messages::{
     CredentialFinalization, CredentialRequest, CredentialResponse, RegistrationRequest,
     RegistrationResponse, RegistrationUpload,
 };
-pub use crate::opaque::{ClientLogin, ClientRegistration, ServerLogin, ServerRegistration};
 pub use crate::opaque::{
-    ClientLoginFinishParameters, ClientLoginStartParameters, ClientRegistrationFinishParameters,
-    ServerLoginStartParameters,
+    ClientLogin, ClientRegistration, ServerLogin, ServerRegistration, ServerSetup,
+};
+pub use crate::opaque::{
+    ClientLoginFinishParameters, ClientRegistrationFinishParameters, ServerLoginStartParameters,
 };
 pub use crate::opaque::{
     ClientLoginFinishResult, ClientLoginStartResult, ClientRegistrationFinishResult,
-    ClientRegistrationStartResult, ServerLoginFinishResult, ServerLoginStartResult,
+    ClientRegistrationStartResult, Identifiers, ServerLoginFinishResult, ServerLoginStartResult,
     ServerRegistrationStartResult,
 };

src/map_to_curve.rs

@@ -6,7 +6,7 @@
 //! Defines the GroupWithMapToCurve trait to specify how to map a password to a
 //! curve point
 
-use crate::errors::{InternalPakeError, ProtocolError};
+use crate::errors::InternalPakeError;
 use crate::group::Group;
 use crate::hash::Hash;
 use crate::serialization::i2osp;
@@ -22,12 +22,16 @@ pub trait GroupWithMapToCurve: Group {
     const SUITE_ID: usize;
 
     /// transforms a password and domain separation tag (DST) into a curve point
-    fn map_to_curve<H: Hash>(msg: &[u8], dst: &[u8]) -> Result<Self, ProtocolError>;
+    fn map_to_curve<H: Hash>(msg: &[u8], dst: &[u8]) -> Result<Self, InternalPakeError>;
+
+    /// Hashes a slice of pseudo-random bytes to a scalar
+    fn hash_to_scalar<H: Hash>(input: &[u8], dst: &[u8])
+        -> Result<Self::Scalar, InternalPakeError>;
 
     /// Generates the contextString parameter as defined in
     /// <https://www.ietf.org/archive/id/draft-irtf-cfrg-voprf-05.txt>
-    fn get_context_string(mode: u8) -> Result<Vec<u8>, ProtocolError> {
-        Ok([i2osp(mode as usize, 1)?, i2osp(Self::SUITE_ID, 2)?].concat())
+    fn get_context_string(mode: u8) -> Vec<u8> {
+        [i2osp(mode as usize, 1), i2osp(Self::SUITE_ID, 2)].concat()
     }
 }
 
@@ -36,13 +40,25 @@ impl GroupWithMapToCurve for RistrettoPoint {
 
     // Implements the hash_to_ristretto255() function from
     // https://www.ietf.org/archive/id/draft-irtf-cfrg-hash-to-curve-10.txt
-    fn map_to_curve<H: Hash>(msg: &[u8], dst: &[u8]) -> Result<Self, ProtocolError> {
+    fn map_to_curve<H: Hash>(msg: &[u8], dst: &[u8]) -> Result<Self, InternalPakeError> {
         let uniform_bytes =
             expand_message_xmd::<H>(msg, dst, <H as Digest>::OutputSize::to_usize())?;
         Ok(<Self as Group>::hash_to_curve(
             &GenericArray::clone_from_slice(&uniform_bytes[..]),
         ))
     }
+
+    fn hash_to_scalar<H: Hash>(
+        input: &[u8],
+        dst: &[u8],
+    ) -> Result<Self::Scalar, InternalPakeError> {
+        const LEN_IN_BYTES: usize = 64;
+        let uniform_bytes = expand_message_xmd::<H>(input, dst, LEN_IN_BYTES)?;
+        let mut bits = [0u8; LEN_IN_BYTES];
+        bits.copy_from_slice(&uniform_bytes[..]);
+
+        Ok(Self::Scalar::from_bytes_mod_order_wide(&bits))
+    }
 }
 
 // Computes ceil(x / y)
@@ -65,24 +81,24 @@ pub(crate) fn expand_message_xmd<H: Hash>(
     msg: &[u8],
     dst: &[u8],
     len_in_bytes: usize,
-) -> Result<Vec<u8>, ProtocolError> {
+) -> Result<Vec<u8>, InternalPakeError> {
     let b_in_bytes = <H as Digest>::OutputSize::to_usize();
     let r_in_bytes = <H as BlockInput>::BlockSize::to_usize();
 
     let ell = div_ceil(len_in_bytes, b_in_bytes);
     if ell > 255 {
-        return Err(InternalPakeError::HashToCurveError.into());
+        return Err(InternalPakeError::HashToCurveError);
     }
-    let dst_prime = [dst, &i2osp(dst.len(), 1)?].concat();
-    let z_pad = i2osp(0, r_in_bytes)?;
-    let l_i_b_str = i2osp(len_in_bytes, 2)?;
-    let msg_prime = [&z_pad, msg, &l_i_b_str, &i2osp(0, 1)?, &dst_prime].concat();
+    let dst_prime = [dst, &i2osp(dst.len(), 1)].concat();
+    let z_pad = i2osp(0, r_in_bytes);
+    let l_i_b_str = i2osp(len_in_bytes, 2);
+    let msg_prime = [&z_pad, msg, &l_i_b_str, &i2osp(0, 1), &dst_prime].concat();
 
     let mut b: Vec<Vec<u8>> = vec![H::digest(&msg_prime).to_vec()]; // b[0]
 
     let mut h = H::new();
     h.update(&b[0]);
-    h.update(&i2osp(1, 1)?);
+    h.update(&i2osp(1, 1));
     h.update(&dst_prime);
     b.push(h.finalize_reset().to_vec()); // b[1]
 
@@ -91,7 +107,7 @@ pub(crate) fn expand_message_xmd<H: Hash>(
 
     for i in 2..(ell + 1) {
         h.update(xor(&b[0], &b[i - 1])?);
-        h.update(&i2osp(i, 1)?);
+        h.update(&i2osp(i, 1));
         h.update(&dst_prime);
         b.push(h.finalize_reset().to_vec()); // b[i]
         uniform_bytes.extend_from_slice(&b[i]);

src/messages.rs

@@ -13,12 +13,14 @@ use crate::{
         PakeError, ProtocolError,
     },
     group::Group,
-    key_exchange::traits::{KeyExchange, ToBytes},
-    keypair::{Key, KeyPair, SizedBytesExt},
+    key_exchange::traits::{FromBytes, KeyExchange, ToBytes},
+    keypair::{KeyPair, PublicKey, SizedBytesExt},
+    opaque::ServerSetup,
 };
+use digest::Digest;
 use generic_array::{typenum::Unsigned, GenericArray};
 use generic_bytes::SizedBytes;
-use std::convert::TryFrom;
+use rand::{CryptoRng, RngCore};
 
 // Messages
 // =========
@@ -44,6 +46,8 @@ impl<CS: CipherSuite> Clone for RegistrationRequest<CS> {
     }
 }
 
+impl_debug_eq_hash_for!(struct RegistrationRequest<CS: CipherSuite>, [alpha], [CS::Group]);
+
 impl<CS: CipherSuite> RegistrationRequest<CS> {
     /// Serialization into bytes
     pub fn serialize(&self) -> Vec<u8> {
@@ -53,7 +57,7 @@ impl<CS: CipherSuite> RegistrationRequest<CS> {
     /// Deserialization from bytes
     pub fn deserialize(input: &[u8]) -> Result<Self, ProtocolError> {
         let elem_len = <CS::Group as Group>::ElemLen::to_usize();
-        let checked_slice = check_slice_size(&input, elem_len, "first_message_bytes")?;
+        let checked_slice = check_slice_size(input, elem_len, "first_message_bytes")?;
         // Check that the message is actually containing an element of the
         // correct subgroup
         let arr = GenericArray::from_slice(checked_slice);
@@ -67,27 +71,45 @@ impl<CS: CipherSuite> RegistrationRequest<CS> {
     }
 }
 
+impl_serialize_and_deserialize_for!(RegistrationRequest);
+
 /// The answer sent by the server to the user, upon reception of the
 /// registration attempt
 pub struct RegistrationResponse<CS: CipherSuite> {
     /// The server's oprf output
     pub(crate) beta: CS::Group,
     /// Server's static public key
-    pub(crate) server_s_pk: Vec<u8>,
+    pub(crate) server_s_pk: PublicKey,
 }
 
+// Cannot be derived because it would require for CS to be Clone.
+impl<CS: CipherSuite> Clone for RegistrationResponse<CS> {
+    fn clone(&self) -> Self {
+        Self {
+            beta: self.beta,
+            server_s_pk: self.server_s_pk.clone(),
+        }
+    }
+}
+
+impl_debug_eq_hash_for!(
+    struct RegistrationResponse<CS: CipherSuite>,
+    [beta, server_s_pk],
+    [CS::Group],
+);
+
 impl<CS: CipherSuite> RegistrationResponse<CS> {
     /// Serialization into bytes
     pub fn serialize(&self) -> Vec<u8> {
-        [self.beta.to_arr().to_vec(), self.server_s_pk.clone()].concat()
+        [self.beta.to_arr().to_vec(), self.server_s_pk.to_vec()].concat()
     }
 
     /// Deserialization from bytes
     pub fn deserialize(input: &[u8]) -> Result<Self, ProtocolError> {
         let elem_len = <CS::Group as Group>::ElemLen::to_usize();
-        let key_len = <Key as SizedBytes>::Len::to_usize();
+        let key_len = <PublicKey as SizedBytes>::Len::to_usize();
         let checked_slice =
-            check_slice_size(&input, elem_len + key_len, "registration_response_bytes")?;
+            check_slice_size(input, elem_len + key_len, "registration_response_bytes")?;
 
         // Check that the message is actually containing an element of the
         // correct subgroup
@@ -100,41 +122,43 @@ impl<CS: CipherSuite> RegistrationResponse<CS> {
         }
 
         // Ensure that public key is valid
-        let server_s_pk =
-            KeyPair::<CS::Group>::check_public_key(Key::from_bytes(&checked_slice[elem_len..])?)?;
+        let server_s_pk = KeyPair::<CS::Group>::check_public_key(PublicKey::from_bytes(
+            &checked_slice[elem_len..],
+        )?)?;
 
-        Ok(Self {
-            beta,
-            server_s_pk: server_s_pk.to_arr().to_vec(),
-        })
-    }
-
-    #[cfg(test)]
-    /// Only used for tests, where we can set the beta value to test for the reflection
-    /// error case
-    pub fn set_beta_for_testing(&self, new_beta: CS::Group) -> Self {
-        Self {
-            beta: new_beta,
-            server_s_pk: self.server_s_pk.clone(),
-        }
+        Ok(Self { server_s_pk, beta })
     }
 }
 
+impl_serialize_and_deserialize_for!(RegistrationResponse);
+
 /// The final message from the client, containing sealed cryptographic
 /// identifiers
 pub struct RegistrationUpload<CS: CipherSuite> {
     /// The "envelope" generated by the user, containing sealed
     /// cryptographic identifiers
-    pub(crate) envelope: Envelope<CS::Hash>,
+    pub(crate) envelope: Envelope<CS>,
+    /// The masking key used to mask the envelope
+    pub(crate) masking_key: GenericArray<u8, <CS::Hash as Digest>::OutputSize>,
     /// The user's public key
-    pub(crate) client_s_pk: Key,
+    pub(crate) client_s_pk: PublicKey,
 }
 
+impl_clone_for!(
+    struct RegistrationUpload<CS: CipherSuite>,
+    [envelope, masking_key, client_s_pk],
+);
+impl_debug_eq_hash_for!(
+    struct RegistrationUpload<CS: CipherSuite>,
+    [envelope, masking_key, client_s_pk],
+);
+
 impl<CS: CipherSuite> RegistrationUpload<CS> {
     /// Serialization into bytes
     pub fn serialize(&self) -> Vec<u8> {
         [
             self.client_s_pk.to_arr().to_vec(),
+            self.masking_key.to_vec(),
             self.envelope.serialize(),
         ]
         .concat()
@@ -142,25 +166,40 @@ impl<CS: CipherSuite> RegistrationUpload<CS> {
 
     /// Deserialization from bytes
     pub fn deserialize(input: &[u8]) -> Result<Self, ProtocolError> {
-        let key_len = <Key as SizedBytes>::Len::to_usize();
-
-        let checked_slice = check_slice_size_atleast(&input, key_len, "registration_upload_bytes")?;
-
-        let (envelope, remainder) = Envelope::<CS::Hash>::deserialize(&checked_slice[key_len..])?;
-
-        if !remainder.is_empty() {
-            return Err(PakeError::SerializationError.into());
-        }
-
+        let key_len = <PublicKey as SizedBytes>::Len::to_usize();
+        let hash_len = <CS::Hash as Digest>::OutputSize::to_usize();
+        let checked_slice =
+            check_slice_size_atleast(input, key_len + hash_len, "registration_upload_bytes")?;
+        let envelope = Envelope::<CS>::deserialize(&checked_slice[key_len + hash_len..])?;
         Ok(Self {
             envelope,
-            client_s_pk: KeyPair::<CS::Group>::check_public_key(Key::from_bytes(
+            masking_key: GenericArray::clone_from_slice(
+                &checked_slice[key_len..key_len + hash_len],
+            ),
+            client_s_pk: KeyPair::<CS::Group>::check_public_key(PublicKey::from_bytes(
                 &checked_slice[..key_len],
             )?)?,
         })
     }
+
+    // Creates a dummy instance used for faking a [CredentialResponse]
+    pub(crate) fn dummy<R: RngCore + CryptoRng>(
+        rng: &mut R,
+        server_setup: &ServerSetup<CS>,
+    ) -> Self {
+        let mut masking_key = vec![0u8; <CS::Hash as Digest>::OutputSize::to_usize()];
+        rng.fill_bytes(&mut masking_key);
+
+        Self {
+            envelope: Envelope::<CS>::dummy(),
+            masking_key: GenericArray::clone_from_slice(&masking_key),
+            client_s_pk: server_setup.fake_keypair.public().clone(),
+        }
+    }
 }
 
+impl_serialize_and_deserialize_for!(RegistrationUpload);
+
 /// The message sent by the user to the server, to initiate registration
 pub struct CredentialRequest<CS: CipherSuite> {
     /// blinded password information
@@ -168,21 +207,36 @@ pub struct CredentialRequest<CS: CipherSuite> {
     pub(crate) ke1_message: <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE1Message,
 }
 
+// Cannot be derived because it would require for CS to be Clone.
+impl<CS: CipherSuite> Clone for CredentialRequest<CS> {
+    fn clone(&self) -> Self {
+        Self {
+            alpha: self.alpha,
+            ke1_message: self.ke1_message.clone(),
+        }
+    }
+}
+
+impl_debug_eq_hash_for!(
+    struct CredentialRequest<CS: CipherSuite>,
+    [alpha, ke1_message],
+    [
+        CS::Group,
+        <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE1Message
+    ],
+);
+
 impl<CS: CipherSuite> CredentialRequest<CS> {
     /// Serialization into bytes
-    pub fn serialize(&self) -> Result<Vec<u8>, ProtocolError> {
-        let mut credential_request: Vec<u8> = Vec::new();
-        credential_request.extend_from_slice(&self.alpha.to_arr());
-        credential_request.extend_from_slice(&self.ke1_message.to_bytes()?);
-        Ok(credential_request)
+    pub fn serialize(&self) -> Vec<u8> {
+        [self.alpha.to_arr().to_vec(), self.ke1_message.to_bytes()].concat()
     }
 
     /// Deserialization from bytes
     pub fn deserialize(input: &[u8]) -> Result<Self, ProtocolError> {
         let elem_len = <CS::Group as Group>::ElemLen::to_usize();
 
-        let checked_slice =
-            check_slice_size_atleast(&input, elem_len, "login_first_message_bytes")?;
+        let checked_slice = check_slice_size_atleast(input, elem_len, "login_first_message_bytes")?;
 
         // Check that the message is actually containing an element of the
         // correct subgroup
@@ -195,60 +249,79 @@ impl<CS: CipherSuite> CredentialRequest<CS> {
         }
 
         let ke1_message =
-            <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE1Message::try_from(
+            <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE1Message::from_bytes::<CS>(
                 &checked_slice[elem_len..],
             )?;
 
         Ok(Self { alpha, ke1_message })
     }
-
-    /// Only used for testing purposes
-    #[cfg(test)]
-    pub fn get_alpha_for_testing(&self) -> CS::Group {
-        self.alpha
-    }
 }
 
+impl_serialize_and_deserialize_for!(CredentialRequest);
+
 /// The answer sent by the server to the user, upon reception of the
 /// login attempt
 pub struct CredentialResponse<CS: CipherSuite> {
     /// the server's oprf output
     pub(crate) beta: CS::Group,
-    pub(crate) server_s_pk: Key,
-    /// the user's sealed information,
-    pub(crate) envelope: Envelope<CS::Hash>,
+    pub(crate) masking_nonce: Vec<u8>,
+    pub(crate) masked_response: Vec<u8>,
     pub(crate) ke2_message: <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE2Message,
 }
 
+// Cannot be derived because it would require for CS to be Clone.
+impl<CS: CipherSuite> Clone for CredentialResponse<CS> {
+    fn clone(&self) -> Self {
+        Self {
+            beta: self.beta,
+            masking_nonce: self.masking_nonce.clone(),
+            masked_response: self.masked_response.clone(),
+            ke2_message: self.ke2_message.clone(),
+        }
+    }
+}
+
+impl_debug_eq_hash_for!(
+    struct CredentialResponse<CS: CipherSuite>,
+    [beta, masking_nonce, masked_response, ke2_message],
+    [
+        CS::Group,
+        <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE2Message,
+    ],
+);
+
 impl<CS: CipherSuite> CredentialResponse<CS> {
     /// Serialization into bytes
-    pub fn serialize(&self) -> Result<Vec<u8>, ProtocolError> {
-        Ok([
-            Self::serialize_without_ke(&self.beta, &self.server_s_pk, &self.envelope),
-            self.ke2_message.to_bytes()?,
+    pub fn serialize(&self) -> Vec<u8> {
+        [
+            Self::serialize_without_ke(&self.beta, &self.masking_nonce, &self.masked_response),
+            self.ke2_message.to_bytes(),
         ]
-        .concat())
+        .concat()
     }
 
     pub(crate) fn serialize_without_ke(
         beta: &CS::Group,
-        server_s_pk: &Key,
-        envelope: &Envelope<CS::Hash>,
+        masking_nonce: &[u8],
+        masked_response: &[u8],
     ) -> Vec<u8> {
-        [
-            &beta.to_arr(),
-            &server_s_pk.to_arr()[..],
-            &envelope.to_bytes(),
-        ]
-        .concat()
+        [&beta.to_arr(), masking_nonce, masked_response].concat()
     }
 
     /// Deserialization from bytes
     pub fn deserialize(input: &[u8]) -> Result<Self, ProtocolError> {
         let elem_len = <CS::Group as Group>::ElemLen::to_usize();
-        let key_len = <Key as SizedBytes>::Len::to_usize();
-        let checked_slice =
-            check_slice_size_atleast(input, elem_len + key_len, "login_second_message_bytes")?;
+        let key_len = <PublicKey as SizedBytes>::Len::to_usize();
+        let nonce_len: usize = 32;
+        let envelope_len = Envelope::<CS>::len();
+        let masked_response_len = key_len + envelope_len;
+        let ke2_message_len = CS::KeyExchange::ke2_message_size();
+
+        let checked_slice = check_slice_size_atleast(
+            input,
+            elem_len + nonce_len + masked_response_len + ke2_message_len,
+            "credential_response_bytes",
+        )?;
 
         // Check that the message is actually containing an element of the
         // correct subgroup
@@ -261,57 +334,53 @@ impl<CS: CipherSuite> CredentialResponse<CS> {
             return Err(PakeError::IdentityGroupElementError.into());
         }
 
-        let unchecked_server_s_pk = Key::from_bytes(&checked_slice[elem_len..elem_len + key_len])?;
-        let server_s_pk = KeyPair::<CS::Group>::check_public_key(unchecked_server_s_pk)?;
-
-        let (envelope, remainder) =
-            Envelope::<CS::Hash>::deserialize(&checked_slice[elem_len + key_len..])?;
-
-        let ke2_message_size = CS::KeyExchange::ke2_message_size();
-        let checked_remainder =
-            check_slice_size_atleast(&remainder, ke2_message_size, "login_second_message_bytes")?;
+        let masking_nonce = checked_slice[elem_len..elem_len + nonce_len].to_vec();
+        let masked_response = checked_slice
+            [elem_len + nonce_len..elem_len + nonce_len + masked_response_len]
+            .to_vec();
         let ke2_message =
-            <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE2Message::try_from(
-                &checked_remainder,
+            <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE2Message::from_bytes::<CS>(
+                &checked_slice[elem_len + nonce_len + masked_response_len..],
             )?;
 
         Ok(Self {
             beta,
-            server_s_pk,
-            envelope,
+            masking_nonce,
+            masked_response,
             ke2_message,
         })
     }
-
-    #[cfg(test)]
-    /// Only used for tests, where we can set the beta value to test for the reflection
-    /// error case
-    pub fn set_beta_for_testing(&self, new_beta: CS::Group) -> Self {
-        Self {
-            beta: new_beta,
-            server_s_pk: self.server_s_pk.clone(),
-            envelope: self.envelope.clone(),
-            ke2_message: self.ke2_message.clone(),
-        }
-    }
 }
 
+impl_serialize_and_deserialize_for!(CredentialResponse);
+
 /// The answer sent by the client to the server, upon reception of the
 /// sealed envelope
 pub struct CredentialFinalization<CS: CipherSuite> {
     pub(crate) ke3_message: <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE3Message,
 }
 
+impl_clone_for!(struct CredentialFinalization<CS: CipherSuite>, [ke3_message]);
+impl_debug_eq_hash_for!(
+    struct CredentialFinalization<CS: CipherSuite>,
+    [ke3_message],
+    [<CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE3Message],
+);
+
 impl<CS: CipherSuite> CredentialFinalization<CS> {
     /// Serialization into bytes
-    pub fn serialize(&self) -> Result<Vec<u8>, ProtocolError> {
+    pub fn serialize(&self) -> Vec<u8> {
         self.ke3_message.to_bytes()
     }
 
     /// Deserialization from bytes
     pub fn deserialize(input: &[u8]) -> Result<Self, ProtocolError> {
         let ke3_message =
-            <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE3Message::try_from(input)?;
+            <CS::KeyExchange as KeyExchange<CS::Hash, CS::Group>>::KE3Message::from_bytes::<CS>(
+                input,
+            )?;
         Ok(Self { ke3_message })
     }
 }
+
+impl_serialize_and_deserialize_for!(CredentialFinalization);

src/oprf.rs

@@ -4,7 +4,7 @@
 // LICENSE file in the root directory of this source tree.
 
 use crate::{
-    errors::ProtocolError, group::Group, hash::Hash, map_to_curve::GroupWithMapToCurve,
+    errors::InternalPakeError, group::Group, hash::Hash, map_to_curve::GroupWithMapToCurve,
     serialization::serialize,
 };
 use digest::Digest;
@@ -12,11 +12,15 @@ use generic_array::GenericArray;
 use rand::{CryptoRng, RngCore};
 
 /// Used to store the OPRF input and blinding factor
+#[cfg_attr(feature = "serialize", derive(serde::Deserialize, serde::Serialize))]
 pub struct Token<Grp: Group> {
     pub(crate) data: Vec<u8>,
     pub(crate) blind: Grp::Scalar,
 }
 
+impl_clone_for!(struct Token<Grp: Group>, [data, blind]);
+impl_debug_eq_hash_for!(struct Token<Grp: Group>, [data, blind], [Grp::Scalar]);
+
 static STR_VOPRF: &[u8] = b"VOPRF06-HashToGroup-";
 static STR_VOPRF_FINALIZE: &[u8] = b"VOPRF06-Finalize-";
 static MODE_BASE: u8 = 0x00;
@@ -28,10 +32,10 @@ static MODE_BASE: u8 = 0x00;
 pub(crate) fn blind<R: RngCore + CryptoRng, G: GroupWithMapToCurve, H: Hash>(
     input: &[u8],
     blinding_factor_rng: &mut R,
-) -> Result<(Token<G>, G), ProtocolError> {
+) -> Result<(Token<G>, G), InternalPakeError> {
     // Choose a random scalar that must be non-zero
     let blind = G::random_nonzero_scalar(blinding_factor_rng);
-    let dst = [STR_VOPRF, &G::get_context_string(MODE_BASE)?].concat();
+    let dst = [STR_VOPRF, &G::get_context_string(MODE_BASE)].concat();
     let mapped_point = G::map_to_curve::<H>(input, &dst)?;
     let blind_token = mapped_point * &blind;
     Ok((
@@ -55,7 +59,7 @@ pub(crate) fn finalize<G: GroupWithMapToCurve, H: Hash>(
     input: &[u8],
     blind: &G::Scalar,
     evaluated_element: G,
-) -> Result<GenericArray<u8, <H as Digest>::OutputSize>, ProtocolError> {
+) -> GenericArray<u8, <H as Digest>::OutputSize> {
     let unblinded_element = evaluated_element * &G::scalar_invert(blind);
     finalize_after_unblind::<G, H>(input, unblinded_element)
 }
@@ -63,15 +67,15 @@ pub(crate) fn finalize<G: GroupWithMapToCurve, H: Hash>(
 fn finalize_after_unblind<G: GroupWithMapToCurve, H: Hash>(
     input: &[u8],
     unblinded_element: G,
-) -> Result<GenericArray<u8, <H as Digest>::OutputSize>, ProtocolError> {
-    let finalize_dst = [STR_VOPRF_FINALIZE, &G::get_context_string(MODE_BASE)?].concat();
+) -> GenericArray<u8, <H as Digest>::OutputSize> {
+    let finalize_dst = [STR_VOPRF_FINALIZE, &G::get_context_string(MODE_BASE)].concat();
     let hash_input = [
-        serialize(input, 2)?,
-        serialize(&unblinded_element.to_arr().to_vec(), 2)?,
-        serialize(&finalize_dst, 2)?,
+        serialize(input, 2),
+        serialize(&unblinded_element.to_arr(), 2),
+        serialize(&finalize_dst, 2),
     ]
     .concat();
-    Ok(<H as Digest>::digest(&hash_input))
+    <H as Digest>::digest(&hash_input)
 }
 
 ////////////////////////
@@ -84,7 +88,7 @@ fn finalize_after_unblind<G: GroupWithMapToCurve, H: Hash>(
 pub fn blind_shim<R: RngCore + CryptoRng, G: GroupWithMapToCurve, H: Hash>(
     input: &[u8],
     blinding_factor_rng: &mut R,
-) -> Result<(Token<G>, G), ProtocolError> {
+) -> Result<(Token<G>, G), InternalPakeError> {
     blind::<R, G, H>(input, blinding_factor_rng)
 }
 
@@ -101,8 +105,8 @@ pub fn evaluate_shim<G: Group>(point: G, oprf_key: &G::Scalar) -> G {
 pub fn finalize_shim<G: GroupWithMapToCurve, H: Hash>(
     token: &Token<G>,
     point: G,
-) -> Result<GenericArray<u8, <H as Digest>::OutputSize>, ProtocolError> {
-    finalize::<G, H>(&token.data, &token.blind, point)
+) -> Result<GenericArray<u8, <H as Digest>::OutputSize>, InternalPakeError> {
+    Ok(finalize::<G, H>(&token.data, &token.blind, point))
 }
 
 ///////////
@@ -120,34 +124,30 @@ mod tests {
     use sha2::Sha512;
 
     fn prf(input: &[u8], oprf_key: &[u8; 32]) -> GenericArray<u8, <Sha512 as Digest>::OutputSize> {
-        let dst = [
-            STR_VOPRF,
-            &RistrettoPoint::get_context_string(MODE_BASE).unwrap(),
-        ]
-        .concat();
+        let dst = [STR_VOPRF, &RistrettoPoint::get_context_string(MODE_BASE)].concat();
         let point = RistrettoPoint::map_to_curve::<Sha512>(input, &dst).unwrap();
         let scalar =
             RistrettoPoint::from_scalar_slice(GenericArray::from_slice(&oprf_key[..])).unwrap();
         let res = point * scalar;
 
-        finalize_after_unblind::<RistrettoPoint, sha2::Sha512>(&input, res).unwrap()
+        finalize_after_unblind::<RistrettoPoint, sha2::Sha512>(input, res)
     }
 
     #[test]
-    fn oprf_retrieval() {
+    fn oprf_retrieval() -> Result<(), InternalPakeError> {
         let input = b"hunter2";
         let mut rng = OsRng;
-        let (token, alpha) = blind::<_, RistrettoPoint, Sha512>(&input[..], &mut rng).unwrap();
+        let (token, alpha) = blind::<_, RistrettoPoint, Sha512>(&input[..], &mut rng)?;
         let oprf_key_bytes = arr![
             u8; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
             24, 25, 26, 27, 28, 29, 30, 31, 32,
         ];
-        let oprf_key = RistrettoPoint::from_scalar_slice(&oprf_key_bytes).unwrap();
+        let oprf_key = RistrettoPoint::from_scalar_slice(&oprf_key_bytes)?;
         let beta = evaluate::<RistrettoPoint>(alpha, &oprf_key);
-        let res =
-            finalize::<RistrettoPoint, sha2::Sha512>(&token.data, &token.blind, beta).unwrap();
-        let res2 = prf(&input[..], &oprf_key.as_bytes());
+        let res = finalize::<RistrettoPoint, sha2::Sha512>(&token.data, &token.blind, beta);
+        let res2 = prf(&input[..], oprf_key.as_bytes());
         assert_eq!(res, res2);
+        Ok(())
     }
 
     #[test]
@@ -156,16 +156,11 @@ mod tests {
         let mut input = vec![0u8; 64];
         rng.fill_bytes(&mut input);
         let (token, alpha) = blind::<_, RistrettoPoint, sha2::Sha512>(&input, &mut rng).unwrap();
-        let res =
-            finalize::<RistrettoPoint, sha2::Sha512>(&token.data, &token.blind, alpha).unwrap();
+        let res = finalize::<RistrettoPoint, sha2::Sha512>(&token.data, &token.blind, alpha);
 
-        let dst = [
-            STR_VOPRF,
-            &RistrettoPoint::get_context_string(MODE_BASE).unwrap(),
-        ]
-        .concat();
+        let dst = [STR_VOPRF, &RistrettoPoint::get_context_string(MODE_BASE)].concat();
         let point = RistrettoPoint::map_to_curve::<Sha512>(&input, &dst).unwrap();
-        let res2 = finalize_after_unblind::<RistrettoPoint, sha2::Sha512>(&input, point).unwrap();
+        let res2 = finalize_after_unblind::<RistrettoPoint, sha2::Sha512>(&input, point);
 
         assert_eq!(res, res2);
     }

src/serialization/mod.rs

@@ -6,24 +6,17 @@
 use crate::errors::PakeError;
 
 // Corresponds to the I2OSP() function from RFC8017
-pub(crate) fn i2osp(input: usize, length: usize) -> Result<Vec<u8>, PakeError> {
-    let sizeof_usize = std::mem::size_of::<usize>();
-
-    // Check if input >= 256^length
-    if (sizeof_usize as u32 - input.leading_zeros() / 8) > length as u32 {
-        return Err(PakeError::SerializationError);
-    }
-
-    if length <= sizeof_usize {
-        return Ok((&input.to_be_bytes()[sizeof_usize - length..]).to_vec());
+pub(crate) fn i2osp(input: usize, length: usize) -> Vec<u8> {
+    if length <= std::mem::size_of::<usize>() {
+        return input.to_be_bytes()[std::mem::size_of::<usize>() - length..].to_vec();
     }
 
     let mut output = vec![0u8; length];
     output.splice(
-        length - sizeof_usize..length,
+        length - std::mem::size_of::<usize>()..length,
         input.to_be_bytes().iter().cloned(),
     );
-    Ok(output)
+    output
 }
 
 // Corresponds to the OS2IP() function from RFC8017
@@ -38,8 +31,8 @@ pub(crate) fn os2ip(input: &[u8]) -> Result<usize, PakeError> {
 }
 
 // Computes I2OSP(len(input), max_bytes) || input
-pub(crate) fn serialize(input: &[u8], max_bytes: usize) -> Result<Vec<u8>, PakeError> {
-    Ok([&i2osp(input.len(), max_bytes)?, input].concat())
+pub(crate) fn serialize(input: &[u8], max_bytes: usize) -> Vec<u8> {
+    [&i2osp(input.len(), max_bytes), input].concat()
 }
 
 // Tokenizes an input of the format I2OSP(len(input), max_bytes) || input, outputting
@@ -60,24 +53,72 @@ pub(crate) fn tokenize(input: &[u8], size_bytes: usize) -> Result<(Vec<u8>, Vec<
     ))
 }
 
+/// Inner macro used for deriving `serde`'s `Serialize` and `Deserialize` traits.
+macro_rules! impl_serialize_and_deserialize_for {
+    ($t:ident) => {
+        #[cfg(feature = "serialize")]
+        impl<CS: CipherSuite> serde::Serialize for $t<CS> {
+            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+            where
+                S: serde::Serializer,
+            {
+                if serializer.is_human_readable() {
+                    serializer.serialize_str(&base64::encode(&self.serialize()))
+                } else {
+                    serializer.serialize_bytes(&self.serialize())
+                }
+            }
+        }
+
+        #[cfg(feature = "serialize")]
+        impl<'de, CS: CipherSuite> serde::Deserialize<'de> for $t<CS> {
+            fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+            where
+                D: serde::Deserializer<'de>,
+            {
+                if deserializer.is_human_readable() {
+                    let s = <&str>::deserialize(deserializer)?;
+                    $t::<CS>::deserialize(&base64::decode(s).map_err(serde::de::Error::custom)?)
+                        .map_err(serde::de::Error::custom)
+                } else {
+                    struct ByteVisitor<CS: CipherSuite> {
+                        marker: std::marker::PhantomData<CS>,
+                    }
+                    impl<'de, CS: CipherSuite> serde::de::Visitor<'de> for ByteVisitor<CS> {
+                        type Value = $t<CS>;
+                        fn expecting(
+                            &self,
+                            formatter: &mut std::fmt::Formatter,
+                        ) -> std::fmt::Result {
+                            formatter.write_str(std::concat!(
+                                "the byte representation of a ",
+                                std::stringify!($t)
+                            ))
+                        }
+
+                        fn visit_bytes<E>(self, value: &[u8]) -> Result<Self::Value, E>
+                        where
+                            E: serde::de::Error,
+                        {
+                            $t::<CS>::deserialize(value).map_err(|_| {
+                                serde::de::Error::invalid_value(
+                                    serde::de::Unexpected::Bytes(value),
+                                    &std::concat!(
+                                        "invalid byte sequence for ",
+                                        std::stringify!($t)
+                                    ),
+                                )
+                            })
+                        }
+                    }
+                    deserializer.deserialize_bytes(ByteVisitor::<CS> {
+                        marker: std::marker::PhantomData,
+                    })
+                }
+            }
+        }
+    };
+}
+
 #[cfg(test)]
 mod tests;
-
-#[cfg(test)]
-mod unit_tests {
-    use super::*;
-
-    // Test the error condition for I2OSP
-    #[test]
-    fn test_i2osp_err_check() {
-        assert!(i2osp(0, 1).is_ok());
-
-        assert!(i2osp(255, 1).is_ok());
-        assert!(i2osp(256, 1).is_err());
-        assert!(i2osp(257, 1).is_err());
-
-        assert!(i2osp(256 * 256 - 1, 2).is_ok());
-        assert!(i2osp(256 * 256, 2).is_err());
-        assert!(i2osp(256 * 256 + 1, 2).is_err());
-    }
-}

src/serialization/tests.rs

@@ -9,10 +9,10 @@ use crate::{
     errors::*,
     group::Group,
     key_exchange::{
-        traits::{KeyExchange, ToBytes},
+        traits::{FromBytes, KeyExchange, ToBytes},
         tripledh::{NonceLen, TripleDH},
     },
-    opaque::*,
+    keypair::{KeyPair, PublicKey},
     serialization::{i2osp, os2ip, serialize},
     *,
 };
@@ -24,7 +24,6 @@ use proptest::{collection::vec, prelude::*};
 use rand::{rngs::OsRng, RngCore};
 
 use sha2::Digest;
-use std::convert::TryFrom;
 
 struct Default;
 impl CipherSuite for Default {
@@ -34,7 +33,7 @@ impl CipherSuite for Default {
     type SlowHash = crate::slow_hash::NoOpHash;
 }
 
-const MAX_INFO_LENGTH: usize = 10;
+const HASH_SIZE: usize = 64; // Because of SHA512
 const MAC_SIZE: usize = 64; // Because of SHA512
 
 fn random_ristretto_point() -> RistrettoPoint {
@@ -56,10 +55,9 @@ fn client_registration_roundtrip() {
     let pw = b"hunter2";
     let mut rng = OsRng;
     let sc = <RistrettoPoint as Group>::random_nonzero_scalar(&mut rng);
-    let elem = <RistrettoPoint as Group>::base_point() * sc;
 
-    // serialization order: scalar, password, group element
-    let bytes: Vec<u8> = [&elem.to_arr(), &sc.as_bytes()[..], &pw[..]].concat();
+    // serialization order: scalar, password
+    let bytes: Vec<u8> = [&sc.as_bytes()[..], &pw[..]].concat();
     let reg = ClientRegistration::<Default>::deserialize(&bytes[..]).unwrap();
     let reg_bytes = reg.serialize();
     assert_eq!(reg_bytes, bytes);
@@ -70,28 +68,20 @@ fn server_registration_roundtrip() {
     // If we don't have envelope and client_pk, the server registration just
     // contains the prf key
     let mut rng = OsRng;
-    let oprf_key = <RistrettoPoint as Group>::random_nonzero_scalar(&mut rng);
-    let mut oprf_bytes: Vec<u8> = vec![];
-    oprf_bytes.extend_from_slice(oprf_key.as_bytes());
-    let reg = ServerRegistration::<Default>::deserialize(&oprf_bytes[..]).unwrap();
-    let reg_bytes = reg.serialize();
-    assert_eq!(reg_bytes, oprf_bytes);
-
-    let mut ciphertext = [0u8; 32];
-    rng.fill_bytes(&mut ciphertext);
+    let mut masking_key = [0u8; HASH_SIZE];
+    rng.fill_bytes(&mut masking_key);
 
     // Construct a mock envelope
     let mut mock_envelope_bytes = Vec::new();
-    mock_envelope_bytes.extend_from_slice(&[1; 1]); // mode = 1
     mock_envelope_bytes.extend_from_slice(&vec![0; NonceLen::to_usize()]); // empty nonce
-    mock_envelope_bytes.extend_from_slice(&ciphertext); // ciphertext which is an encrypted private key
+                                                                           // mock_envelope_bytes.extend_from_slice(&ciphertext); // ciphertext which is an encrypted private key
     mock_envelope_bytes.extend_from_slice(&[0; MAC_SIZE]); // length-MAC_SIZE hmac
 
-    let mock_client_kp = Default::generate_random_keypair(&mut rng);
+    let mock_client_kp = KeyPair::<<Default as CipherSuite>::Group>::generate_random(&mut rng);
     // serialization order: oprf_key, public key, envelope
     let mut bytes = Vec::<u8>::new();
-    bytes.extend_from_slice(oprf_key.as_bytes());
     bytes.extend_from_slice(&mock_client_kp.public().to_arr());
+    bytes.extend_from_slice(&masking_key);
     bytes.extend_from_slice(&mock_envelope_bytes);
     let reg = ServerRegistration::<Default>::deserialize(&bytes[..]).unwrap();
     let reg_bytes = reg.serialize();
@@ -114,12 +104,12 @@ fn registration_request_roundtrip() {
     let identity = RistrettoPoint::identity();
     let identity_bytes = identity.to_arr().to_vec();
 
-    assert!(
-        match RegistrationRequest::<Default>::deserialize(identity_bytes.as_slice()) {
-            Err(ProtocolError::VerificationError(PakeError::IdentityGroupElementError)) => true,
-            _ => false,
-        }
-    );
+    assert!(matches!(
+        RegistrationRequest::<Default>::deserialize(identity_bytes.as_slice()),
+        Err(ProtocolError::VerificationError(
+            PakeError::IdentityGroupElementError
+        ))
+    ));
 }
 
 #[test]
@@ -127,12 +117,12 @@ fn registration_response_roundtrip() {
     let pt = random_ristretto_point();
     let beta_bytes = pt.to_arr();
     let mut rng = OsRng;
-    let skp = Default::generate_random_keypair(&mut rng);
+    let skp = KeyPair::<<Default as CipherSuite>::Group>::generate_random(&mut rng);
     let pubkey_bytes = skp.public().to_arr();
 
     let mut input = Vec::new();
     input.extend_from_slice(beta_bytes.as_slice());
-    input.extend_from_slice(&pubkey_bytes.as_slice());
+    input.extend_from_slice(pubkey_bytes.as_slice());
 
     let r2 = RegistrationResponse::<Default>::deserialize(input.as_slice()).unwrap();
     let r2_bytes = r2.serialize();
@@ -142,38 +132,38 @@ fn registration_response_roundtrip() {
     let identity = RistrettoPoint::identity();
     let identity_bytes = identity.to_arr().to_vec();
 
-    assert!(match RegistrationResponse::<Default>::deserialize(
-        &[identity_bytes, pubkey_bytes.to_vec()].concat()
-    ) {
-        Err(ProtocolError::VerificationError(PakeError::IdentityGroupElementError)) => true,
-        _ => false,
-    });
+    assert!(matches!(
+        RegistrationResponse::<Default>::deserialize(
+            &[identity_bytes, pubkey_bytes.to_vec()].concat()
+        ),
+        Err(ProtocolError::VerificationError(
+            PakeError::IdentityGroupElementError
+        ))
+    ));
 }
 
 #[test]
 fn registration_upload_roundtrip() {
     let mut rng = OsRng;
-    let skp = Default::generate_random_keypair(&mut rng);
+    let skp = KeyPair::<<Default as CipherSuite>::Group>::generate_random(&mut rng);
     let pubkey_bytes = skp.public().to_arr();
 
     let mut key = [0u8; 32];
     rng.fill_bytes(&mut key);
+    let mut nonce = [0u8; 32];
+    rng.fill_bytes(&mut nonce);
 
-    let mut msg = [0u8; 32];
-    rng.fill_bytes(&mut msg);
+    let mut masking_key = vec![0u8; <sha2::Sha512 as Digest>::OutputSize::to_usize()];
+    rng.fill_bytes(&mut masking_key);
 
-    let (envelope, _) = Envelope::<sha2::Sha512>::seal_raw(
-        &mut rng,
-        &key,
-        &msg,
-        &pubkey_bytes,
-        InnerEnvelopeMode::Base,
-    )
-    .unwrap();
+    let (envelope, _) =
+        Envelope::<Default>::seal_raw(&key, &nonce, &pubkey_bytes, InnerEnvelopeMode::Internal)
+            .unwrap();
     let envelope_bytes = envelope.serialize();
 
     let mut input = Vec::new();
     input.extend_from_slice(&pubkey_bytes[..]);
+    input.extend_from_slice(&masking_key[..]);
     input.extend_from_slice(&envelope_bytes);
 
     let r3 = RegistrationUpload::<Default>::deserialize(&input[..]).unwrap();
@@ -187,38 +177,30 @@ fn credential_request_roundtrip() {
     let alpha = random_ristretto_point();
     let alpha_bytes = alpha.to_arr().to_vec();
 
-    let client_e_kp = Default::generate_random_keypair(&mut rng);
+    let client_e_kp = KeyPair::<<Default as CipherSuite>::Group>::generate_random(&mut rng);
     let mut client_nonce = vec![0u8; NonceLen::to_usize()];
     rng.fill_bytes(&mut client_nonce);
 
-    let mut info = [0u8; MAX_INFO_LENGTH];
-    rng.fill_bytes(&mut info);
-
-    let ke1m: Vec<u8> = [
-        &client_nonce[..],
-        &serialize(&info.to_vec(), 2).unwrap(),
-        &client_e_kp.public(),
-    ]
-    .concat();
+    let ke1m: Vec<u8> = [&client_nonce[..], client_e_kp.public()].concat();
 
     let mut input = Vec::new();
     input.extend_from_slice(&alpha_bytes);
     input.extend_from_slice(&ke1m[..]);
 
     let l1 = CredentialRequest::<Default>::deserialize(input.as_slice()).unwrap();
-    let l1_bytes = l1.serialize().unwrap();
+    let l1_bytes = l1.serialize();
     assert_eq!(input, l1_bytes);
 
     // Assert that identity group element is rejected
     let identity = RistrettoPoint::identity();
     let identity_bytes = identity.to_arr().to_vec();
 
-    assert!(match CredentialRequest::<Default>::deserialize(
-        &[identity_bytes, ke1m.to_vec()].concat()
-    ) {
-        Err(ProtocolError::VerificationError(PakeError::IdentityGroupElementError)) => true,
-        _ => false,
-    });
+    assert!(matches!(
+        CredentialRequest::<Default>::deserialize(&[identity_bytes, ke1m.to_vec()].concat()),
+        Err(ProtocolError::VerificationError(
+            PakeError::IdentityGroupElementError
+        ))
+    ));
 }
 
 #[test]
@@ -227,69 +209,50 @@ fn credential_response_roundtrip() {
     let pt_bytes = pt.to_arr().to_vec();
 
     let mut rng = OsRng;
-    let skp = Default::generate_random_keypair(&mut rng);
-    let pubkey_bytes = skp.public().to_arr();
 
-    let mut key = [0u8; 32];
-    rng.fill_bytes(&mut key);
+    let mut masking_nonce = vec![0u8; 32];
+    rng.fill_bytes(&mut masking_nonce);
 
-    let mut msg = [0u8; 32];
-    rng.fill_bytes(&mut msg);
+    let mut masked_response =
+        vec![0u8; <PublicKey as SizedBytes>::Len::to_usize() + Envelope::<Default>::len()];
+    rng.fill_bytes(&mut masked_response);
 
-    let (envelope, _) = Envelope::<sha2::Sha512>::seal_raw(
-        &mut rng,
-        &key,
-        &msg,
-        &pubkey_bytes,
-        InnerEnvelopeMode::Base,
-    )
-    .unwrap();
-
-    let server_e_kp = Default::generate_random_keypair(&mut rng);
+    let server_e_kp = KeyPair::<<Default as CipherSuite>::Group>::generate_random(&mut rng);
     let mut mac = [0u8; MAC_SIZE];
     rng.fill_bytes(&mut mac);
     let mut server_nonce = vec![0u8; NonceLen::to_usize()];
     rng.fill_bytes(&mut server_nonce);
 
-    let mut e_info = [0u8; MAX_INFO_LENGTH];
-    rng.fill_bytes(&mut e_info);
-
-    let ke2m: Vec<u8> = [
-        &server_nonce[..],
-        &server_e_kp.public(),
-        &serialize(&e_info.to_vec(), 2).unwrap(),
-        &mac[..],
-    ]
-    .concat();
-
-    let serialized_envelope = envelope.serialize();
+    let ke2m: Vec<u8> = [&server_nonce[..], server_e_kp.public(), &mac[..]].concat();
 
     let mut input = Vec::new();
     input.extend_from_slice(pt_bytes.as_slice());
-    input.extend_from_slice(&pubkey_bytes.as_slice());
-    input.extend_from_slice(&serialized_envelope);
+    input.extend_from_slice(&masking_nonce);
+    input.extend_from_slice(&masked_response);
     input.extend_from_slice(&ke2m[..]);
 
     let l2 = CredentialResponse::<Default>::deserialize(&input).unwrap();
-    let l2_bytes = l2.serialize().unwrap();
+    let l2_bytes = l2.serialize();
     assert_eq!(input, l2_bytes);
 
     // Assert that identity group element is rejected
     let identity = RistrettoPoint::identity();
     let identity_bytes = identity.to_arr().to_vec();
 
-    assert!(match CredentialResponse::<Default>::deserialize(
-        &[
-            identity_bytes,
-            pubkey_bytes.to_vec(),
-            serialized_envelope,
-            ke2m.to_vec()
-        ]
-        .concat()
-    ) {
-        Err(ProtocolError::VerificationError(PakeError::IdentityGroupElementError)) => true,
-        _ => false,
-    });
+    assert!(matches!(
+        CredentialResponse::<Default>::deserialize(
+            &[
+                identity_bytes,
+                masking_nonce.to_vec(),
+                masked_response,
+                ke2m.to_vec()
+            ]
+            .concat()
+        ),
+        Err(ProtocolError::VerificationError(
+            PakeError::IdentityGroupElementError
+        ))
+    ));
 }
 
 #[test]
@@ -301,7 +264,7 @@ fn login_third_message_roundtrip() {
     let input: Vec<u8> = [&mac[..]].concat();
 
     let l3 = CredentialFinalization::<Default>::deserialize(&input).unwrap();
-    let l3_bytes = l3.serialize().unwrap();
+    let l3_bytes = l3.serialize();
     assert_eq!(input, l3_bytes);
 }
 
@@ -311,7 +274,7 @@ fn client_login_roundtrip() {
     let mut rng = OsRng;
     let sc = <RistrettoPoint as Group>::random_nonzero_scalar(&mut rng);
 
-    let client_e_kp = Default::generate_random_keypair(&mut rng);
+    let client_e_kp = KeyPair::<<Default as CipherSuite>::Group>::generate_random(&mut rng);
     let mut client_nonce = vec![0u8; NonceLen::to_usize()];
     rng.fill_bytes(&mut client_nonce);
 
@@ -321,13 +284,13 @@ fn client_login_roundtrip() {
     // serialization order: scalar, credential_request, ke1_state, password
     let bytes: Vec<u8> = [
         &sc.as_bytes()[..],
-        &serialize(&serialized_credential_request, 2).unwrap(),
-        &serialize(&l1_data, 2).unwrap(),
+        &serialize(&serialized_credential_request, 2),
+        &serialize(&l1_data, 2),
         &pw[..],
     ]
     .concat();
     let reg = ClientLogin::<Default>::deserialize(&bytes[..]).unwrap();
-    let reg_bytes = reg.serialize().unwrap();
+    let reg_bytes = reg.serialize();
     assert_eq!(reg_bytes, bytes);
 }
 
@@ -335,23 +298,16 @@ fn client_login_roundtrip() {
 fn ke1_message_roundtrip() {
     let mut rng = OsRng;
 
-    let client_e_kp = Default::generate_random_keypair(&mut rng);
+    let client_e_kp = KeyPair::<<Default as CipherSuite>::Group>::generate_random(&mut rng);
     let mut client_nonce = vec![0u8; NonceLen::to_usize()];
     rng.fill_bytes(&mut client_nonce);
 
-    let mut info = [0u8; MAX_INFO_LENGTH];
-    rng.fill_bytes(&mut info);
-
-    let ke1m: Vec<u8> = [
-        &client_nonce[..],
-        &serialize(&info.to_vec(), 2).unwrap(),
-        &client_e_kp.public(),
-    ]
-    .concat();
-    let reg =
-        <TripleDH as KeyExchange<sha2::Sha512, RistrettoPoint>>::KE1Message::try_from(&ke1m[..])
-            .unwrap();
-    let reg_bytes = reg.to_bytes().unwrap();
+    let ke1m: Vec<u8> = [&client_nonce[..], client_e_kp.public()].concat();
+    let reg = <TripleDH as KeyExchange<sha2::Sha512, RistrettoPoint>>::KE1Message::from_bytes::<
+        Default,
+    >(&ke1m[..])
+    .unwrap();
+    let reg_bytes = reg.to_bytes();
     assert_eq!(reg_bytes, ke1m);
 }
 
@@ -359,26 +315,19 @@ fn ke1_message_roundtrip() {
 fn ke2_message_roundtrip() {
     let mut rng = OsRng;
 
-    let server_e_kp = Default::generate_random_keypair(&mut rng);
+    let server_e_kp = KeyPair::<<Default as CipherSuite>::Group>::generate_random(&mut rng);
     let mut mac = [0u8; MAC_SIZE];
     rng.fill_bytes(&mut mac);
     let mut server_nonce = vec![0u8; NonceLen::to_usize()];
     rng.fill_bytes(&mut server_nonce);
-    let mut e_info = [0u8; MAX_INFO_LENGTH];
-    rng.fill_bytes(&mut e_info);
 
-    let ke2m: Vec<u8> = [
-        &server_nonce[..],
-        &server_e_kp.public(),
-        &serialize(&e_info.to_vec(), 2).unwrap(),
-        &mac[..],
-    ]
-    .concat();
+    let ke2m: Vec<u8> = [&server_nonce[..], server_e_kp.public(), &mac[..]].concat();
 
-    let reg =
-        <TripleDH as KeyExchange<sha2::Sha512, RistrettoPoint>>::KE2Message::try_from(&ke2m[..])
-            .unwrap();
-    let reg_bytes = reg.to_bytes().unwrap();
+    let reg = <TripleDH as KeyExchange<sha2::Sha512, RistrettoPoint>>::KE2Message::from_bytes::<
+        Default,
+    >(&ke2m[..])
+    .unwrap();
+    let reg_bytes = reg.to_bytes();
     assert_eq!(reg_bytes, ke2m);
 }
 
@@ -390,67 +339,68 @@ fn ke3_message_roundtrip() {
 
     let ke3m: Vec<u8> = [&mac[..]].concat();
 
-    let reg =
-        <TripleDH as KeyExchange<sha2::Sha512, RistrettoPoint>>::KE3Message::try_from(&ke3m[..])
-            .unwrap();
-    let reg_bytes = reg.to_bytes().unwrap();
+    let reg = <TripleDH as KeyExchange<sha2::Sha512, RistrettoPoint>>::KE3Message::from_bytes::<
+        Default,
+    >(&ke3m[..])
+    .unwrap();
+    let reg_bytes = reg.to_bytes();
     assert_eq!(reg_bytes, ke3m);
 }
 
 proptest! {
 
 #[test]
-fn test_i2osp_os2ip(bytes in vec(any::<u8>(), 0..std::mem::size_of::<usize>())) {
-    assert_eq!(i2osp(os2ip(&bytes)?, bytes.len())?, bytes);
+fn test_i2osp_os2ip(ref bytes in vec(prop::num::u8::ANY, 0..std::mem::size_of::<usize>())) {
+    assert_eq!(&i2osp(os2ip(bytes)?, bytes.len()), bytes);
 }
 
 #[test]
-fn test_nocrash_registration_request(bytes in vec(any::<u8>(), 0..200)) {
+fn test_nocrash_registration_request(ref bytes in vec(prop::num::u8::ANY, 0..200)) {
     RegistrationRequest::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_registration_response(bytes in vec(any::<u8>(), 0..200)) {
+fn test_nocrash_registration_response(ref bytes in vec(prop::num::u8::ANY, 0..200)) {
     RegistrationResponse::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_registration_upload(bytes in vec(any::<u8>(), 0..200)) {
+fn test_nocrash_registration_upload(ref bytes in vec(prop::num::u8::ANY, 0..200)) {
     RegistrationUpload::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_credential_request(bytes in vec(any::<u8>(), 0..500)) {
+fn test_nocrash_credential_request(ref bytes in vec(prop::num::u8::ANY, 0..500)) {
     CredentialRequest::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_credential_response(bytes in vec(any::<u8>(), 0..500)) {
+fn test_nocrash_credential_response(ref bytes in vec(prop::num::u8::ANY, 0..500)) {
     CredentialResponse::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_credential_finalization(bytes in vec(any::<u8>(), 0..500)) {
+fn test_nocrash_credential_finalization(ref bytes in vec(prop::num::u8::ANY, 0..500)) {
     CredentialFinalization::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_client_registration(bytes in vec(any::<u8>(), 0..700)) {
+fn test_nocrash_client_registration(ref bytes in vec(prop::num::u8::ANY, 0..700)) {
     ClientRegistration::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_server_registration(bytes in vec(any::<u8>(), 0..700)) {
+fn test_nocrash_server_registration(ref bytes in vec(prop::num::u8::ANY, 0..700)) {
     ServerRegistration::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_client_login(bytes in vec(any::<u8>(), 0..700)) {
+fn test_nocrash_client_login(ref bytes in vec(prop::num::u8::ANY, 0..700)) {
     ClientLogin::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 
 #[test]
-fn test_nocrash_server_login(bytes in vec(any::<u8>(), 0..700)) {
+fn test_nocrash_server_login(ref bytes in vec(prop::num::u8::ANY, 0..700)) {
     ServerLogin::<Default>::deserialize(&bytes[..]).map_or(true, |_| true);
 }
 

src/slow_hash.rs

@@ -31,22 +31,20 @@ impl<D: Hash> SlowHash<D> for NoOpHash {
 }
 
 #[cfg(feature = "slow-hash")]
-const DEFAULT_SCRYPT_LOG_N: u8 = 15u8;
-#[cfg(feature = "slow-hash")]
-const DEFAULT_SCRYPT_R: u32 = 8u32;
-#[cfg(feature = "slow-hash")]
-const DEFAULT_SCRYPT_P: u32 = 1u32;
-
-#[cfg(feature = "slow-hash")]
-impl<D: Hash> SlowHash<D> for scrypt::ScryptParams {
+impl<D: Hash> SlowHash<D> for argon2::Argon2<'_> {
     fn hash(
         input: GenericArray<u8, <D as Digest>::OutputSize>,
     ) -> Result<Vec<u8>, InternalPakeError> {
-        let params =
-            scrypt::ScryptParams::new(DEFAULT_SCRYPT_LOG_N, DEFAULT_SCRYPT_R, DEFAULT_SCRYPT_P)
-                .map_err(|_| InternalPakeError::SlowHashError)?;
+        let params = argon2::Argon2::default();
         let mut output = vec![0u8; <D as Digest>::OutputSize::to_usize()];
-        scrypt::scrypt(&input, &[], &params, &mut output)
+        params
+            .hash_password_into(
+                argon2::Algorithm::Argon2id,
+                &input,
+                &[0; argon2::MIN_SALT_LENGTH],
+                &[],
+                &mut output,
+            )
             .map_err(|_| InternalPakeError::SlowHashError)?;
         Ok(output)
     }

src/tests/mock_rng.rs

@@ -48,7 +48,7 @@ impl RngCore for CycleRng {
     #[inline]
     fn fill_bytes(&mut self, dest: &mut [u8]) {
         let len = min(self.v.len(), dest.len());
-        (&mut dest[..len]).copy_from_slice(&self.v[..len]);
+        dest[..len].copy_from_slice(&self.v[..len]);
         rotate_left(&mut self.v, len);
     }
 

src/tests/opaque_test_vectors.rs

@@ -4,16 +4,12 @@
 // LICENSE file in the root directory of this source tree.
 
 use crate::{
-    ciphersuite::CipherSuite,
-    errors::*,
-    key_exchange::tripledh::TripleDH,
-    keypair::{Key, SizedBytesExt},
-    opaque::*,
-    slow_hash::NoOpHash,
-    tests::mock_rng::CycleRng,
-    *,
+    ciphersuite::CipherSuite, errors::*, key_exchange::tripledh::TripleDH, keypair::PrivateKey,
+    opaque::*, slow_hash::NoOpHash, tests::mock_rng::CycleRng, *,
 };
 use curve25519_dalek::ristretto::RistrettoPoint;
+use generic_array::typenum::Unsigned;
+use generic_bytes::SizedBytes;
 use serde_json::Value;
 
 // Tests
@@ -27,7 +23,7 @@ impl CipherSuite for Ristretto255Sha512NoSlowHash {
     type SlowHash = NoOpHash;
 }
 
-#[derive(PartialEq)]
+#[derive(PartialEq, Eq)]
 pub enum EnvelopeMode {
     Base,
     CustomIdentifier,
@@ -35,20 +31,24 @@ pub enum EnvelopeMode {
 
 #[allow(non_snake_case)]
 pub struct TestVectorParameters {
+    pub dummy_private_key: Vec<u8>,
+    pub dummy_masking_key: Vec<u8>,
+    pub context: Vec<u8>,
     pub envelope_mode: EnvelopeMode,
-    pub client_public_key: Vec<u8>,
-    pub client_private_key: Vec<u8>,
+    pub client_private_key: Option<Vec<u8>>,
     pub client_keyshare: Vec<u8>,
     pub client_private_keyshare: Vec<u8>,
     pub server_public_key: Vec<u8>,
     pub server_private_key: Vec<u8>,
     pub server_keyshare: Vec<u8>,
     pub server_private_keyshare: Vec<u8>,
-    pub client_identity: Vec<u8>,
-    pub server_identity: Vec<u8>,
+    pub client_identity: Option<Vec<u8>>,
+    pub server_identity: Option<Vec<u8>>,
+    pub credential_identifier: Vec<u8>,
     pub password: Vec<u8>,
     pub blind_registration: Vec<u8>,
-    pub oprf_key: Vec<u8>,
+    pub oprf_seed: Vec<u8>,
+    pub masking_nonce: Vec<u8>,
     pub envelope_nonce: Vec<u8>,
     pub client_nonce: Vec<u8>,
     pub server_nonce: Vec<u8>,
@@ -69,206 +69,329 @@ pub struct TestVectorParameters {
 // of https://datatracker.ietf.org/doc/draft-irtf-cfrg-opaque/
 static TEST_VECTORS: &[&str] = &[
     r#"
+## OPAQUE-3DH Test Vector 1
+
+### Configuration
+
+~~~
 OPRF: 0001
 Hash: SHA512
-SlowHash: Identity
+MHF: Identity
+KDF: HKDF-SHA512
+MAC: HMAC-SHA512
 EnvelopeMode: 01
 Group: ristretto255
+Context: 4f50415155452d504f43
 Nh: 64
 Npk: 32
 Nsk: 32
+Nm: 64
+Nx: 64
+Nok: 32
+~~~
+
+### Input Values
+
+~~~
+oprf_seed: 5c4f99877d253be5817b4b03f37b6da680b0d5671d1ec5351fa61c5d82
+eab28b9de4c4e170f27e433ba377c71c49aa62ad26391ee1cac17011d8a7e9406657c
+8
+credential_identifier: 31323334
 password: 436f7272656374486f72736542617474657279537461706c65
-envelope_nonce: cc7abb200199d5071c94efa49fb62435d3e70d03cf9573a95da54
-20d3eebcd2b
-client_private_key: 8bcb0b70dac18de24eef12e737d6b28724d3e37774e0b092f
-9f70b255defaf04
-client_public_key: 360e716c676cfe4d9968d1a352ed3faf17603863e0a7aa1905
-df6ea129343b09
-server_private_key: f3a0829898a89239dce29ccc98ec8b449a34b255ba1e6f944
-829d18e0d589b0f
-server_public_key: 66e130c6eb5b41f851b235b03a0eafeaa883f64147bc62cb74
-9c22c762389c3c
-client_info: 68656c6c6f20626f62
-server_info: 6772656574696e677320616c696365
-server_nonce: 98b8081059f60ffed9336f026fd8e124737205ac73f5348ae5bebdb
-49456c70f
-client_nonce: 58dc21475ff730342f807bf031c7ae47a11f0d4dfaa63a7feb15d7e
-36427ca44
-server_keyshare: 5214e3ddc73db786480b79fa2da787f2080b82cbe922c2a9592b
-44597d9a702e
-client_keyshare: a4084c7296b1a3d5a5e4a24358750489575acfd8fcfa6e787492
-b98265a5e651
-server_private_keyshare: c4d002aa4cfcf281657cf36fe562bc60d9133e0e72a7
-4432f685b2b6a4b42a0c
-client_private_keyshare: de2e98f422bf7b99be19f7da7cac62f1599d35a225ec
-6340149a0aaff3102003
-blind_registration: 7e5bcbf82a46109ee0d24e9bcab41fc830a6ce8b82fc1e921
-3a043b743b95800
-blind_login: c4d5a15f0d5ffc354e340454ec779f575e4573a3886ab5e57e4da298
-4bdd5306
-oprf_key: 080d0a4d352de92672ab709b1ae1888cb48dfabc2d6ca5b914b335512fe
-70508
-auth_key: 7bb7f2b831ee30d3e5cc4012c8f721a4d8f9dd494932d53776e043df9bd
-2aa284025b8b006fd8449536446ff50698f46c73fccb53f20d80898f185307d1d39e5
-prk: b0aefddbb21d1b97bc40c07b172e0bf172ec740de4f6274f69d46350a447e9b1
-b3fb1e4cefc7d8e393ff58a5c45c74d0615ee0eecde116f3d4e744142eb2ee89
-pseudorandom_pad: 36a828b3b57bf242c4c47ccd9cb84e5b3cefaffe09629c6b94d
-eba0ccec5fa39
-envelope: 01cc7abb200199d5071c94efa49fb62435d3e70d03cf9573a95da5420d3
-eebcd2bbd6323c36fba7fa08a2b6e2aab6efcdc183c4c897d822cf96d29b129932a55
-3d469ffa9999fcbd37a1e8b6c1e579bcf83fed355c9ff413e6158d72d16f3ccd8699e
-906027842694b6293b6303bbb7f324e0fccb4ae0f01edb60ee1d32992696e
-handshake_secret: 2b041dcf12ac9b75dded88f891c25d76746ce9e2c1a43118ac4
-aa5721cdc1bc2f0691e6c012a1ea9eb95ab4899b3e7058d37fe9546c46b0511877e40
-f55aac6c
-handshake_encrypt_key: ceef10f15d869a4cea8174fa98d0d96c7aaf8602d006fe
-0c5274a40173db76cac820138c5890bb63fb974d1e3e925850cc2464e2c10f0a9a776
-9a45e80889b1e
-server_mac_key: f8fd7fdc349b5ae1339515e05912c89a795f561a117cdc84d8d8b
-5f05b05751abfb87fa01c799c5d367244d1e32eab67ff926833c6025c556acffa4af1
-f3871a
-client_mac_key: 92a30cc82c374c06895aa07e81f0cf5f25309a24b595faefcd225
-1f9219b47e47d17da4fe8b572dedefa350ed365f87b217973e90d0b647a2ccf1d796a
-8970f6
-registration_request: ec9027daa5e9a901d641286a7ded51364142936ac7636e1
-42e3f4368b4bd8124
-registration_response: 8867d7c8c2c576a6322d49d46078ea32f479aed917c70a
-636d3ada4397ea1c0e66e130c6eb5b41f851b235b03a0eafeaa883f64147bc62cb749
-c22c762389c3c
-registration_upload: 360e716c676cfe4d9968d1a352ed3faf17603863e0a7aa19
-05df6ea129343b0901cc7abb200199d5071c94efa49fb62435d3e70d03cf9573a95da
-5420d3eebcd2bbd6323c36fba7fa08a2b6e2aab6efcdc183c4c897d822cf96d29b129
-932a553d469ffa9999fcbd37a1e8b6c1e579bcf83fed355c9ff413e6158d72d16f3cc
-d8699e906027842694b6293b6303bbb7f324e0fccb4ae0f01edb60ee1d32992696e
-KE1: e06a32011e1b1704eb686b263e5d132fff4e9f6429cd93b98db107485006792c
-58dc21475ff730342f807bf031c7ae47a11f0d4dfaa63a7feb15d7e36427ca4400096
-8656c6c6f20626f62a4084c7296b1a3d5a5e4a24358750489575acfd8fcfa6e787492
-b98265a5e651
-KE2: 66f6b5fa1a4eb6bd7a0c93ed2639a31cba0d02e2df744003641d5a30a4a12364
-66e130c6eb5b41f851b235b03a0eafeaa883f64147bc62cb749c22c762389c3c01cc7
-abb200199d5071c94efa49fb62435d3e70d03cf9573a95da5420d3eebcd2bbd6323c3
-6fba7fa08a2b6e2aab6efcdc183c4c897d822cf96d29b129932a553d469ffa9999fcb
-d37a1e8b6c1e579bcf83fed355c9ff413e6158d72d16f3ccd8699e906027842694b62
-93b6303bbb7f324e0fccb4ae0f01edb60ee1d32992696e98b8081059f60ffed9336f0
-26fd8e124737205ac73f5348ae5bebdb49456c70f5214e3ddc73db786480b79fa2da7
-87f2080b82cbe922c2a9592b44597d9a702e000f72f38a0945819089c44c86820c51d
-89cc35f77df03d330101bbed3b2f69066112f32529bdda0998657350fc9f8da4cde73
-408ad931f4c2ea6237ccae4696483388b174f50cf96d439139b0f8680c3b
-KE3: 9f0e4f73455ca9fe06bb52ad02670b09be5a03db11a73be4422f19963be082b0
-eb55871022e8d1d87adc3ab50de7c738058eb659866d091648f2fed12e23fd53
-export_key: 66c0b72aa829f13a166fb1a1168f1e26023921f0eed1126def4f81ba0
-4924ad6012e42b63656ec199ba27670d1e7f23dc0a927714edc140134dde5a5d2063d
-fc
-session_key: 951c2bb1b876725fa7d3829db791dddd406a688507b47e24101bd0cc
-5d071760b6fba59e8758a6ea6d7e5f51a715b49a47c50fee9a7c8a0451243c3ee837f
-d30
+envelope_nonce: 71b8f14b7a1059cdadc414c409064a22cf9e970b0ffc6f1fc6fdd
+539c4676775
+masking_nonce: 54f9341ca183700f6b6acf28dbfe4a86afad788805de49f2d680ab
+86ff39ed7f
+server_private_key: 16eb9dc74a3df2033cd738bf2cfb7a3670c569d7749f284b2
+b241cb237e7d10f
+server_public_key: 18d5035fd0a9c1d6412226df037125901a43f4dff660c0549d
+402f672bcc0933
+server_nonce: f9c5ec75a8cd571370add249e99cb8a8c43f6ef05610ac6e354642b
+f4fedbf69
+client_nonce: 804133133e7ee6836c8515752e24bb44d323fef4ead34cde967798f
+2e9784f69
+server_keyshare: 6e77d4749eb304c4d74be9457c597546bc22aed699225499910f
+c913b3e90712
+client_keyshare: f67926bd036c5dc4971816b9376e9f64737f361ef8269c18f69f
+1ab555e96d4a
+server_private_keyshare: f8e3e31543dd6fc86833296726773d51158291ab9afd
+666bb55dce83474c1101
+client_private_keyshare: 4230d62ea740b13e178185fc517cf2c313e6908c4cd9
+fb42154870ff3490c608
+blind_registration: c62937d17dc9aa213c9038f84fe8c5bf3d953356db01c4d48
+acb7cae48e6a504
+blind_login: b5f458822ea11c900ad776e38e29d7be361f75b4d79b55ad74923299
+bf8d6503
+oprf_key: 23d431bab39aea4d2737ac391a50076300210730971788e3a6a8c29ad3c
+5930e
+~~~
+
+### Intermediate Values
+
+~~~
+client_public_key: f692d6b738b4e240d5f59d534371363b47817c00c7058d4a33
+439911e66c3c27
+auth_key: 27972f9b1cf2ce524d50a7afa40a2ee6957904e2bef29976bdbda452a84
+fcf01023f3ddd8182e64ea5287f99765dd39b83fa89fe189db227212a144134684783
+randomized_pwd: 750ef06299c2fb102242fd84e59613616338f83e69c09c1dc3f91
+c57ac0642876ccbe785e94aa094262efdc6aed08b3faff7c1bddfa14c434c5a908ad6
+c5f9d5
+envelope: 71b8f14b7a1059cdadc414c409064a22cf9e970b0ffc6f1fc6fdd539c46
+76775455739db882585a7c8b3e9ae7955da7135900d85ab832aa83a34b3ce481efc9e
+43d4c2276220c8bcb9d27b5a827a5a2d655700321f3b32d21f578c21316195d8
+handshake_secret: 02fb23a668b7138b029c95d21f1e0eec9e10377be933bdbf3e5
+33ea39073d3ce9d1ef16b55a8a8464f3bf6a991cc645d14c1fa3d9d6cfe36c6c0dcc2
+691d7109
+server_mac_key: e75ce46beeebd26f22540d7988de9809a69cf34fec6c050750708
+e91232297fdbb51e875cd37167d5ce661ebccf0004dbbf96311daf64ddec7faae04c4
+8bbd89
+client_mac_key: 4bce132daa031fff2a6e5ac29287c4641e3b9dc2560394b8c73f3
+b748f1e51e577b932a960b236981217b33bee220b0bce2696638cfb7791f427ade292
+d60f55
+~~~
+
+### Output Values
+
+~~~
+registration_request: 80576bce33c6ce89f9e1a06d8595cd9d09d9aef46b20dad
+d57a845dc50e7c074
+registration_response: 1a80fdb4f4eb1985587b5b95661d2cff1ef2493cdcdd88
+b5699f39048f0d6c2618d5035fd0a9c1d6412226df037125901a43f4dff660c0549d4
+02f672bcc0933
+registration_upload: f692d6b738b4e240d5f59d534371363b47817c00c7058d4a
+33439911e66c3c2795014d8fc0c710bd763c981c5b9329c95e149c6717af91bad2cec
+daf87f2c3c9c11914cb6d44aaee5679e3e61e1b65241fda74902cca908a065495c0b2
+8b799e71b8f14b7a1059cdadc414c409064a22cf9e970b0ffc6f1fc6fdd539c467677
+5455739db882585a7c8b3e9ae7955da7135900d85ab832aa83a34b3ce481efc9e43d4
+c2276220c8bcb9d27b5a827a5a2d655700321f3b32d21f578c21316195d8
+KE1: 60d71c9f5d2a14568807b869e2c251a8e5f7ad8951cd8386c7e32c0634b26b16
+804133133e7ee6836c8515752e24bb44d323fef4ead34cde967798f2e9784f69f6792
+6bd036c5dc4971816b9376e9f64737f361ef8269c18f69f1ab555e96d4a
+KE2: 78a428204f552d3532bad040c961324edb22c738d98f1dd770d65caba0bd8966
+54f9341ca183700f6b6acf28dbfe4a86afad788805de49f2d680ab86ff39ed7fbcbbb
+84a18810b8eb1dc898d9af686f5901a21d0768720b325279fde4931ee52f0d4a0d0d9
+cd1cd7c424d4622b1588ba554cd9241352a59ef52bbe85e0f865021404b115ba954f5
+540cf2d811a6566a93876cac1239b1f75f39b070250af5a84a819e08b13e9e437a80f
+c25cc130f8475dde43efe6d900c664e9bac300298bb0f9c5ec75a8cd571370add249e
+99cb8a8c43f6ef05610ac6e354642bf4fedbf696e77d4749eb304c4d74be9457c5975
+46bc22aed699225499910fc913b3e907120485942e3e077f71c1dd2d87053b39f0d31
+bfe5d5f90df0e85ad9ce771e4f4d1ab697a10a02002cd73916051b887da9554465d58
+68811fd8b22b8f457ed5a4b0
+KE3: b4f8aece9fb4f6b7b5ffe1c98747a91f4ec7bf5481fe5719ba4baad668e3fd4e
+8aba4fa227bd4c688ed9e17f6c6d28ab5e5617a883207d80979dc4797ca89304
+export_key: 045f61f4baa0a945c2e85dfb7a85fe4df8a49e6c31344920e863c286b
+c8a17fe25fc16c84836335b4b5ecc9743c5d3a221101ab004aa99ce65026b6953ad6c
+c0
+session_key: 91187690e5ea0da3110a1dd7d5ffd7c4c3111950c587d9fcf3b9f34b
+f73b86dbeafed42a05024fa875a32415c6143d20c39cd732eb0e31db5e60ea3fb2551
+cf7
+~~~
 "#,
     r#"
+## OPAQUE-3DH Test Vector 2
+
+### Configuration
+
+~~~
 OPRF: 0001
 Hash: SHA512
-SlowHash: Identity
-EnvelopeMode: 02
+MHF: Identity
+KDF: HKDF-SHA512
+MAC: HMAC-SHA512
+EnvelopeMode: 01
 Group: ristretto255
+Context: 4f50415155452d504f43
 Nh: 64
 Npk: 32
 Nsk: 32
-client_identity: 20fa92f2e4b7ea5b5e677ac4930ff3b93b0043481ab70bc613b2
-e16a6dde6b05
-server_identity: eae9dfa6b8348d34418c32d385e1eac99efbce1af320901f7c8e
-de8d6d272c65
+Nm: 64
+Nx: 64
+Nok: 32
+~~~
+
+### Input Values
+
+~~~
+client_identity: 616c696365
+server_identity: 626f62
+oprf_seed: db5c1c16e264b8933d5da56439e7cfed23ab7287b474fe3cdcd58df089
+a365a426ea849258d9f4bc13573601f2e727c90ecc19d448cf3145a662e0065f157ba
+5
+credential_identifier: 31323334
 password: 436f7272656374486f72736542617474657279537461706c65
-envelope_nonce: f41e8b3c5a999aa946f9b562a150e5c5e36748a31a79feb241809
-0438877888c
-client_private_key: dc70a99bbabf1ebe98b192e93cedceb9c0164e95b891bd8bc
-81721b83d66b00b
-client_public_key: 20fa92f2e4b7ea5b5e677ac4930ff3b93b0043481ab70bc613
-b2e16a6dde6b05
-server_private_key: 709687a36c94592ab76579f42ce1be6961f0700496e71df80
-6ebd5320554720d
-server_public_key: eae9dfa6b8348d34418c32d385e1eac99efbce1af320901f7c
-8ede8d6d272c65
-client_info: 68656c6c6f20626f62
-server_info: 6772656574696e677320616c696365
-server_nonce: ef49d83cef5f1411ea30abb82b08bd85423aadb86e2c19df5930b3c
-8498b9f97
-client_nonce: 4ab1227db632bc079f79c0f5279df2dfa75cfbd4434ab40dcf844d6
-77165cd3b
-server_keyshare: 96a9587e233e67f2397f10fec6355b68102534f1f1b115b4ddf7
-485840efcd7c
-client_keyshare: 54f35db3a52fb0cf2a97918a6987993231d227e28711eaef19a3
-e5033632611a
-server_private_keyshare: 6650d64df70618a878504ce73dcca27b1af125c67e48
-1e7bd49d0b24709b200f
-client_private_keyshare: ebb01c59f99bc955df622548e247f7ef180732909ff3
-c5f87ff8c7867b8be704
-blind_registration: 308f1d3fa1fea402f3c90b04601274050a3c6f467387c2f48
-878823949b0e109
-blind_login: 141e21373228a44b09d4c00da9a6bbaf9a5e54a1687c07f327833643
-4245510b
-oprf_key: b7126967aa0cb69c311b71343843ea041bae30e2bde41b548b8fbd8bced
-97604
-auth_key: 9f761a5a56a74269b382403aeba47c1d24b9e200e1839efcb616fb280da
-1b6ba7bd71d6455dd3cd979c545608cfbfc1c4e9ba677e1d40848054a00696c4b2589
-prk: 30bc3f37a757890ac17ce46043f3c5ed30c96fb8743205e77e84dc167d98e114
-6093150ff7b4d002f793bfe717e88d174ed2669abdd9e96af473a7ac82973b0a
-pseudorandom_pad: b909f990c94b9c5949a2b8d0874d602f846b7981b331fd79978
-b530cc46c8670
-envelope: 02f41e8b3c5a999aa946f9b562a150e5c5e36748a31a79feb2418090438
-877888c6579500b73f482e7d1132a39bba0ae96447d37140ba040f25f9c72b4f90a36
-7bdb425fa1dd4c49e17780f33b821e1e019668fe7f45520e26996ac8cb08e3d2566cc
-439c83030464effecb8350e7b1ca31087d87f6a45ed3910c185a24a89d282
-handshake_secret: ff89f264f8c3974238f4c8d736af7b0a55f2e4edc487cbf3e5c
-7b4bbf21acd7c1d28354c2c8555fba57c4d4b1fbb4b772bfdf909881f67dd517cc9f4
-f6ebaeac
-handshake_encrypt_key: 3071b181f639062cf70b74d0ffe5ec8fa695da13cd2f00
-e74b8b7ef348ae7a5df9c3a32c9f7aeaad5a28379712cf849b9707e221dce124abfad
-d0225a8e8e045
-server_mac_key: 7c37b344d189cbbeff80bbb4b78e2703d1a80dc28239923094287
-62f7ce2a93b11f6e85dd45c02809afe8583d4aad6377e72788773af92eef33c690692
-20ae76
-client_mac_key: 2c4aff12ba7aa911a51f9e5b7a7c01439d854c97e4b8ec842a9db
-d78345760328fd5a72424e49e25ec8fe1b6d9d42f774516f400948bd5a105d995d000
-2fc83b
-registration_request: 3c8b89966e261a5aaf7aeb6dcdd94c87ce311bf197221b8
-7ef44632d58f18a05
-registration_response: caf9243d7ef3e267815632bf79c85a27a23f218a438815
-2a523f6a310949807beae9dfa6b8348d34418c32d385e1eac99efbce1af320901f7c8
-ede8d6d272c65
-registration_upload: 20fa92f2e4b7ea5b5e677ac4930ff3b93b0043481ab70bc6
-13b2e16a6dde6b0502f41e8b3c5a999aa946f9b562a150e5c5e36748a31a79feb2418
-090438877888c6579500b73f482e7d1132a39bba0ae96447d37140ba040f25f9c72b4
-f90a367bdb425fa1dd4c49e17780f33b821e1e019668fe7f45520e26996ac8cb08e3d
-2566cc439c83030464effecb8350e7b1ca31087d87f6a45ed3910c185a24a89d282
-KE1: 8261a1efd78bea73faf256a23c200d729259886530fa43b875c1ca124b09bc7e
-4ab1227db632bc079f79c0f5279df2dfa75cfbd4434ab40dcf844d677165cd3b00096
-8656c6c6f20626f6254f35db3a52fb0cf2a97918a6987993231d227e28711eaef19a3
-e5033632611a
-KE2: fa1f33a43a03123ebe35345ef93aa23b57ea8bfbee7022b05a179d60768ba02e
-eae9dfa6b8348d34418c32d385e1eac99efbce1af320901f7c8ede8d6d272c6502f41
-e8b3c5a999aa946f9b562a150e5c5e36748a31a79feb2418090438877888c6579500b
-73f482e7d1132a39bba0ae96447d37140ba040f25f9c72b4f90a367bdb425fa1dd4c4
-9e17780f33b821e1e019668fe7f45520e26996ac8cb08e3d2566cc439c83030464eff
-ecb8350e7b1ca31087d87f6a45ed3910c185a24a89d282ef49d83cef5f1411ea30abb
-82b08bd85423aadb86e2c19df5930b3c8498b9f9796a9587e233e67f2397f10fec635
-5b68102534f1f1b115b4ddf7485840efcd7c000f7ebe71d4ab326006a3aeca802435d
-c995a38ac6662221f974cb920992d82b8ef8d147c77e29b628a82b5ccb01ea2f7bb60
-af94cd1860e1bd974a11a1c9bd827789f663c4758eb71058c244138de0c2
-KE3: d81f93397cdba85a43993d4d9afbdc67f147adfa2b223213b19692cb820eef48
-5073eda4c8236b2f47702404ad60d9a875d189626fc7b7cc861825385470ae54
-export_key: 03192555940b5b42e64e6200bf55cc701f1bace3d402a2f8d83977843
-51a1e3fa1f07a471b783b208acb1d92be47903b6fa3a0df9f4d4b7956ee4f431e2950
+envelope_nonce: d0c7b0f0047682bd87a87e0c3553b9bcdce7e1ae3348570df20bf
+2747829b2d2
+masking_nonce: 30635396b708ddb7fc10fb73c4e3a9258cd9c3f6f761b2c227853b
+5def228c85
+server_private_key: eeb2fcc794f98501b16139771720a0713a2750b9e528adfd3
+662ad56a7e19b04
+server_public_key: 8aa90cb321a38759fc253c444f317782962ca18d33101eab2c
+8cda04405a181f
+server_nonce: 3fa57f7ef652185f89114109f5a61cc8c9216fdd7398246bb7a0c20
+e2fbca2d8
+client_nonce: a6bcd29b5aecc3507fc1f8f7631af3d2f5105155222e48099e5e608
+5d8c1187a
+server_keyshare: ae070cdffe5bb4b1c373e71be8e7d8f356ee5de37881533f1039
+7bcd84d35445
+client_keyshare: 642e7eecf19b804a62817486663d6c6c239396f709b663a4350c
+da67d025687a
+server_private_keyshare: 0974010a8528b813f5b33ae0d791df88516c8839c152
+b030697637878b2d8b0a
+client_private_keyshare: 03b52f066898929f4aca48014b2b97365205ce691ee3
+444b0a7cecec3c7efb01
+blind_registration: a66ffb41ccf1194a8d7dda900f8b6b0652e4c7fac4610066f
+e0489a804d3bb05
+blind_login: e6f161ac189e6873a19a54efca4baa0719e801e336d929d35ca28b5b
+4f60560e
+oprf_key: 1e0550d2dbb9ce5dd9bdbb5f808afbb724c573dc03306dcfc7217796465
+ce607
+~~~
+
+### Intermediate Values
+
+~~~
+client_public_key: ba6cb41f1870e9db7e858440a664e6559d01fdbfb638bbf7e1
+c9004f20d5db71
+auth_key: 5142ae6f6bd80686039656fd7a03cdd7e39cc6e869aa637220d4b5fb64f
+afee2f284a1581fff95ad3a5261b413c5e5b91115f78a3c35486fa56023c300d1726b
+randomized_pwd: cea240b632b9c1d704034920cc3dc3c664ed8cd82cf5c0339af76
+4d6350d2ee9ba1f675ce8df7b6cf8692d1efb158bafa3c2695ac03a2d92346c19810c
+1a698b
+envelope: d0c7b0f0047682bd87a87e0c3553b9bcdce7e1ae3348570df20bf274782
+9b2d26e18240c0cbad3b4cdbd7d9d86512f87e43fac39e3785a17504aaa8508f81e3c
+1517b150259be478720935e175b1e34bbe625d0828a62ca9983f9a27aed27f5e
+handshake_secret: 7925c12d7bf3050e62fe5c8caaece3c85737754c5df79bc59a6
+0fa87929ab1f4a4730f903b87be8b7d89ded8ec97aaec97bc8e7d53a555fd4ad74c4f
+33b9bc83
+server_mac_key: 27d6036335c5654132fb08cc81d95b3067ef7fe795f017531231a
+e3fa03cd3ab72f1f5e81473318f9c01f990263d885dfce4b6ac8630fdc8ee8abc6a36
+7c2339
+client_mac_key: ebb3693bac6310075a89922c7a40599d14d03d9104b7a331106e8
+a578a32a4944751f9d3c230a6690a5747137388a86159cf587969d13dadc0a3830218
+dfbca5
+~~~
+
+### Output Values
+
+~~~
+registration_request: f841cbb85844967568c7405f3831a58c4f5f37ccddb0baa
+4972ea912c960ae66
+registration_response: 0256257cc6e2b04444edc076b9ad44d8b31593e050bea8
+06485707a818f8a93f8aa90cb321a38759fc253c444f317782962ca18d33101eab2c8
+cda04405a181f
+registration_upload: ba6cb41f1870e9db7e858440a664e6559d01fdbfb638bbf7
+e1c9004f20d5db71146e42585d25fa19913876edce4b5ee99b638eb37b1d8a8a76607
+efaa12299e828641ba4fbf1c46fc2c3776e0a0c9791f88a15b9ddfb5495d63ce92d8f
+58823bd0c7b0f0047682bd87a87e0c3553b9bcdce7e1ae3348570df20bf2747829b2d
+26e18240c0cbad3b4cdbd7d9d86512f87e43fac39e3785a17504aaa8508f81e3c1517
+b150259be478720935e175b1e34bbe625d0828a62ca9983f9a27aed27f5e
+KE1: 14cc586d982b6db9846c78e0b3c543591e95fbf2fc877fa0e5eff89897dd3050
+a6bcd29b5aecc3507fc1f8f7631af3d2f5105155222e48099e5e6085d8c1187a642e7
+eecf19b804a62817486663d6c6c239396f709b663a4350cda67d025687a
+KE2: 8ab71c17547f376ae787741c367142790087090cdde6327dabb2581197bffa59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+KE3: c4a0d5b8148f3ac0f8611b38de38bda085d4eb00d561397ae59676f36dc705be
+1c939e7bfdd7301103af5eb164bdfb70298aab889bd2ac797e419a82bfb442e6
+export_key: 6b50ae4dba956930c0465b4a26c3cee58e05afcab623c1c254ae34acc
+38babf954530a53475672ff46a1cf7fd53ef9e808f85b08793d021bb5c6d2a1bb9204
 f6
-session_key: 58a7fa98bf3b7b52da21406abfb11d98734354edd47d7b32462c0513
-f0617c89824ea6031d4147a86fc9f6c6837ce640c12fb937d764f296d1a9421ad1b2a
-5d5
+session_key: c9bc2b7e2237f6fbeccd92dc6ec6d51faeb886492f8d23f21743a967
+597025215df02a4afb75349acbafeef9dfd4f19e6d38da8bea4912f7b691b70849b0d
+78e
+~~~
 "#,
 ];
 
+static FAKE_TEST_VECTORS: &[&str] = &[r#"
+### OPAQUE-3DH Fake Test Vector 1
+
+#### Configuration
+
+~~~
+OPRF: 0001
+Hash: SHA512
+MHF: Identity
+KDF: HKDF-SHA512
+MAC: HMAC-SHA512
+EnvelopeMode: 01
+Group: ristretto255
+Context: 4f50415155452d504f43
+Nh: 64
+Npk: 32
+Nsk: 32
+Nm: 64
+Nx: 64
+Nok: 32
+~~~
+
+#### Input Values
+
+~~~
+client_identity: 616c696365
+server_identity: 626f62
+oprf_seed: d3cb00535339fe4063c7ba5506a990c243a2b5c77b06848a0be9a0568c
+252fb0d7425382babd267deeed669e56d1d5654c036211f49b42f4489f96f37100779
+f
+credential_identifier: 31323334
+masking_nonce: 3058799f42516228746821dc8c8530d0e8273ebde81941591d69ca
+5aea773090
+client_private_key: 83c9bcc31a9da0ffa4489900d3d1f85bb65c27f26e9ae4e3b
+66f6e02e098c503
+client_public_key: 56717b74a5e1770edb14c65f22cee0487046bd96e122ba97da
+ffed06c4bf4052
+server_private_key: 8d3a9355f9757e7071b3f836e3fb1461a6436e92971625b17
+cd7e580dd27c009
+server_public_key: 7a464761cb19c8b6e832fdfcfd18779b0edc246fe808f5de6c
+e7bdb54df41b67
+server_nonce: 4e2a8098173efa2968036f1762f2e5df41ab976fb1bfb91dae29950
+f8526de4c
+server_keyshare: 0e247410004d83d7cbe3af89c62ff03f942127aec4b0084c9eb5
+88e74ce6dd06
+server_private_keyshare: 326345820acc8aacf4948fce775a1fd265e4e93fd579
+cec8177d6389ee379b0a
+masking_key: e968bfe56ad934c3e1088115bcbf1af8b405fd0de94cdf301f9192cc
+2781de00617e568b14b7235cc1189265811ea354031ea39b62e31a104f181c01d3dae
+4b8
+KE1: 480b6c0066c9320c50dce20f8b6b63e4ded7681defd9da3f70ecdc15770f9e68
+05603c1acb64ea417c0dabaab858a5f9da046d4a0cdbf092034c00451ccdc6e1ee835
+5c91d5ed7aa5ea75b8a730ba8dc45f6b41ae9713e6aa7126211346e8754
+~~~
+
+#### Output Values
+
+~~~
+KE2: 04013bca360b4b9ba95b2f494927375e0f234dac23053822e466a9738f781522
+3058799f42516228746821dc8c8530d0e8273ebde81941591d69ca5aea77309078577
+13efdc95f69166737cd7a80ead60e1a1f805c1da9cccbc0d29120f34be291518798c7
+00793f232374e66182495b76b388d9e11f479580cc2297da02fecee88a99cea6bc411
+b9467e8bfa9a4006aba7f21b74b4ce3bccd686785878b0ec9b3fc4200228014d5d073
+69d42d1d1b1669ecd2ad8905734ca0a641d8f16667ca4e2a8098173efa2968036f176
+2f2e5df41ab976fb1bfb91dae29950f8526de4c0e247410004d83d7cbe3af89c62ff0
+3f942127aec4b0084c9eb588e74ce6dd06fb1a0fd81da51bc1d87c740c186d881ed79
+71fdba5ad1d5cfc94ffe6a731241c78ea7ea5dae503e987edc37355b7348883dc65cd
+b57aec04e64593007f98a405
+~~~
+"#];
+
 macro_rules! parse {
     ( $v:ident, $s:expr ) => {
+        parse_default!($v, $s, vec![])
+    };
+}
+
+macro_rules! parse_default {
+    ( $v:ident, $s:expr, $d:expr ) => {
         match decode(&$v, $s) {
             Some(x) => x,
-            None => vec![],
+            None => $d,
         }
     };
 }
@@ -285,20 +408,24 @@ fn rfc_to_json(input: &str) -> String {
     let mut json = vec![];
     for line in input.lines() {
         // If line contains colon, then
-        if line.contains(":") {
-            if json.len() > 0 {
+        if line.contains(':') {
+            if !json.is_empty() {
                 // Adding closing quote for previous line, comma, and newline
                 json.push("\",\n".to_string());
             }
 
-            let mut iter = line.split(":");
+            let mut iter = line.split(':');
             let key = iter.next().unwrap().split_whitespace().next().unwrap();
             let val = iter.next().unwrap().split_whitespace().next().unwrap();
 
             json.push(format!("    \"{}\": \"{}", key, val));
         } else {
             let s = line.trim().to_string();
-            if s.len() > 0 {
+            if s.contains('~') || s.contains('#') {
+                // Ignore comment lines
+                continue;
+            }
+            if !s.is_empty() {
                 json.push(s);
             }
         }
@@ -308,31 +435,37 @@ fn rfc_to_json(input: &str) -> String {
 }
 
 fn decode(values: &Value, key: &str) -> Option<Vec<u8>> {
-    values[key]
-        .as_str()
-        .and_then(|s| hex::decode(&s.to_string()).ok())
+    values[key].as_str().and_then(|s| hex::decode(s).ok())
 }
 
 fn populate_test_vectors(values: &Value) -> TestVectorParameters {
     TestVectorParameters {
+        dummy_private_key: parse_default!(
+            values,
+            "client_private_key",
+            vec![0u8; <PrivateKey as SizedBytes>::Len::to_usize()]
+        ),
+        dummy_masking_key: parse_default!(values, "masking_key", vec![0u8; 64]),
+        context: parse!(values, "Context"),
         envelope_mode: match values["EnvelopeMode"].as_str() {
             Some("01") => EnvelopeMode::Base,
             Some("02") => EnvelopeMode::CustomIdentifier,
             _ => panic!("Could not match envelope mode"),
         },
-        client_public_key: parse!(values, "client_public_key"),
-        client_private_key: parse!(values, "client_private_key"),
+        client_private_key: decode(values, "client_private_key"),
         client_keyshare: parse!(values, "client_keyshare"),
         client_private_keyshare: parse!(values, "client_private_keyshare"),
         server_public_key: parse!(values, "server_public_key"),
         server_private_key: parse!(values, "server_private_key"),
         server_keyshare: parse!(values, "server_keyshare"),
         server_private_keyshare: parse!(values, "server_private_keyshare"),
-        client_identity: parse!(values, "client_identity"),
-        server_identity: parse!(values, "server_identity"),
+        client_identity: decode(values, "client_identity"),
+        server_identity: decode(values, "server_identity"),
+        credential_identifier: parse!(values, "credential_identifier"),
         password: parse!(values, "password"),
         blind_registration: parse!(values, "blind_registration"),
-        oprf_key: parse!(values, "oprf_key"),
+        oprf_seed: parse!(values, "oprf_seed"),
+        masking_nonce: parse!(values, "masking_nonce"),
         envelope_nonce: parse!(values, "envelope_nonce"),
         client_nonce: parse!(values, "client_nonce"),
         server_nonce: parse!(values, "server_nonce"),
@@ -351,21 +484,25 @@ fn populate_test_vectors(values: &Value) -> TestVectorParameters {
 }
 
 fn get_password_file_bytes(parameters: &TestVectorParameters) -> Result<Vec<u8>, ProtocolError> {
-    let mut oprf_key_rng = CycleRng::new(parameters.oprf_key.clone());
-    let server_registration_start_result =
-        ServerRegistration::<Ristretto255Sha512NoSlowHash>::start(
-            &mut oprf_key_rng,
-            RegistrationRequest::deserialize(&parameters.registration_request[..]).unwrap(),
-            &Key::from_bytes(&parameters.server_public_key[..]).unwrap(),
-        )?;
-
-    let password_file = server_registration_start_result
-        .state
-        .finish(RegistrationUpload::deserialize(&parameters.registration_upload[..]).unwrap())?;
+    let password_file = ServerRegistration::<Ristretto255Sha512NoSlowHash>::finish(
+        RegistrationUpload::deserialize(&parameters.registration_upload[..]).unwrap(),
+    );
 
     Ok(password_file.serialize())
 }
 
+fn parse_identifiers(
+    client_identity: Option<Vec<u8>>,
+    server_identity: Option<Vec<u8>>,
+) -> Option<Identifiers> {
+    match (client_identity, server_identity) {
+        (None, None) => None,
+        (Some(x), None) => Some(Identifiers::ClientIdentifier(x)),
+        (None, Some(y)) => Some(Identifiers::ServerIdentifier(y)),
+        (Some(x), Some(y)) => Some(Identifiers::ClientAndServerIdentifiers(x, y)),
+    }
+}
+
 #[test]
 fn test_registration_request() -> Result<(), ProtocolError> {
     for parameters in rfc_to_params!(TEST_VECTORS) {
@@ -386,12 +523,19 @@ fn test_registration_request() -> Result<(), ProtocolError> {
 #[test]
 fn test_registration_response() -> Result<(), ProtocolError> {
     for parameters in rfc_to_params!(TEST_VECTORS) {
-        let mut oprf_key_rng = CycleRng::new(parameters.oprf_key);
+        let server_setup = ServerSetup::<Ristretto255Sha512NoSlowHash>::deserialize(
+            &[
+                &parameters.oprf_seed[..],
+                &parameters.server_private_key[..],
+                &parameters.dummy_private_key[..],
+            ]
+            .concat(),
+        )?;
         let server_registration_start_result =
             ServerRegistration::<Ristretto255Sha512NoSlowHash>::start(
-                &mut oprf_key_rng,
+                &server_setup,
                 RegistrationRequest::deserialize(&parameters.registration_request[..]).unwrap(),
-                &Key::from_bytes(&parameters.server_public_key[..]).unwrap(),
+                &parameters.credential_identifier,
             )?;
         assert_eq!(
             hex::encode(parameters.registration_response),
@@ -411,19 +555,13 @@ fn test_registration_upload() -> Result<(), ProtocolError> {
                 &parameters.password,
             )?;
 
-        let sk_u_and_nonce: Vec<u8> =
-            [parameters.client_private_key, parameters.envelope_nonce].concat();
-        let mut finish_registration_rng = CycleRng::new(sk_u_and_nonce);
+        let mut finish_registration_rng = CycleRng::new(parameters.envelope_nonce);
         let result = client_registration_start_result.state.finish(
             &mut finish_registration_rng,
             RegistrationResponse::deserialize(&parameters.registration_response[..]).unwrap(),
-            if parameters.envelope_mode == EnvelopeMode::CustomIdentifier {
-                ClientRegistrationFinishParameters::WithIdentifiers(
-                    parameters.client_identity,
-                    parameters.server_identity,
-                )
-            } else {
-                ClientRegistrationFinishParameters::default()
+            match parse_identifiers(parameters.client_identity, parameters.server_identity) {
+                None => ClientRegistrationFinishParameters::Default,
+                Some(ids) => ClientRegistrationFinishParameters::WithIdentifiers(ids),
             },
         )?;
 
@@ -433,7 +571,7 @@ fn test_registration_upload() -> Result<(), ProtocolError> {
         );
         assert_eq!(
             hex::encode(parameters.export_key),
-            hex::encode(result.export_key.to_vec())
+            hex::encode(result.export_key)
         );
     }
 
@@ -453,11 +591,10 @@ fn test_ke1() -> Result<(), ProtocolError> {
         let client_login_start_result = ClientLogin::<Ristretto255Sha512NoSlowHash>::start(
             &mut client_login_start_rng,
             &parameters.password,
-            ClientLoginStartParameters::WithInfo(parameters.client_info),
         )?;
         assert_eq!(
             hex::encode(&parameters.KE1),
-            hex::encode(client_login_start_result.message.serialize()?)
+            hex::encode(client_login_start_result.message.serialize())
         );
     }
     Ok(())
@@ -466,33 +603,45 @@ fn test_ke1() -> Result<(), ProtocolError> {
 #[test]
 fn test_ke2() -> Result<(), ProtocolError> {
     for parameters in rfc_to_params!(TEST_VECTORS) {
-        let password_file_bytes = get_password_file_bytes(&parameters)?;
+        let server_setup = ServerSetup::<Ristretto255Sha512NoSlowHash>::deserialize(
+            &[
+                &parameters.oprf_seed[..],
+                &parameters.server_private_key[..],
+                &parameters.dummy_private_key[..],
+            ]
+            .concat(),
+        )?;
 
-        let mut server_private_keyshare_and_nonce_rng =
-            CycleRng::new([parameters.server_private_keyshare, parameters.server_nonce].concat());
+        let record = ServerRegistration::<Ristretto255Sha512NoSlowHash>::deserialize(
+            &get_password_file_bytes(&parameters)?[..],
+        )?;
+
+        let mut server_private_keyshare_and_nonce_rng = CycleRng::new(
+            [
+                parameters.masking_nonce,
+                parameters.server_private_keyshare,
+                parameters.server_nonce,
+            ]
+            .concat(),
+        );
         let server_login_start_result = ServerLogin::<Ristretto255Sha512NoSlowHash>::start(
             &mut server_private_keyshare_and_nonce_rng,
-            ServerRegistration::deserialize(&password_file_bytes[..]).unwrap(),
-            &Key::from_bytes(&parameters.server_private_key[..]).unwrap(),
+            &server_setup,
+            Some(record),
             CredentialRequest::<Ristretto255Sha512NoSlowHash>::deserialize(&parameters.KE1[..])
                 .unwrap(),
-            if parameters.envelope_mode == EnvelopeMode::CustomIdentifier {
-                ServerLoginStartParameters::WithInfoAndIdentifiers(
-                    parameters.server_info.to_vec(),
-                    parameters.client_identity,
-                    parameters.server_identity,
-                )
-            } else {
-                ServerLoginStartParameters::WithInfo(parameters.server_info.to_vec())
+            &parameters.credential_identifier,
+            match parse_identifiers(parameters.client_identity, parameters.server_identity) {
+                None => ServerLoginStartParameters::WithContext(parameters.context.to_vec()),
+                Some(ids) => ServerLoginStartParameters::WithContextAndIdentifiers(
+                    parameters.context.to_vec(),
+                    ids,
+                ),
             },
         )?;
-        assert_eq!(
-            hex::encode(&parameters.client_info),
-            hex::encode(server_login_start_result.plain_info),
-        );
         assert_eq!(
             hex::encode(&parameters.KE2),
-            hex::encode(server_login_start_result.message.serialize()?)
+            hex::encode(server_login_start_result.message.serialize())
         );
     }
     Ok(())
@@ -511,32 +660,25 @@ fn test_ke3() -> Result<(), ProtocolError> {
         let client_login_start_result = ClientLogin::<Ristretto255Sha512NoSlowHash>::start(
             &mut client_login_start_rng,
             &parameters.password,
-            ClientLoginStartParameters::WithInfo(parameters.client_info),
         )?;
 
         let client_login_finish_result = client_login_start_result.state.finish(
             CredentialResponse::<Ristretto255Sha512NoSlowHash>::deserialize(&parameters.KE2[..])?,
-            if parameters.envelope_mode == EnvelopeMode::CustomIdentifier {
-                ClientLoginFinishParameters::WithIdentifiers(
-                    parameters.client_identity,
-                    parameters.server_identity,
-                )
-            } else {
-                ClientLoginFinishParameters::default()
+            match parse_identifiers(parameters.client_identity, parameters.server_identity) {
+                None => ClientLoginFinishParameters::WithContext(parameters.context),
+                Some(ids) => {
+                    ClientLoginFinishParameters::WithContextAndIdentifiers(parameters.context, ids)
+                }
             },
         )?;
 
-        assert_eq!(
-            hex::encode(&parameters.server_info),
-            hex::encode(&client_login_finish_result.confidential_info)
-        );
         assert_eq!(
             hex::encode(&parameters.session_key),
             hex::encode(&client_login_finish_result.session_key)
         );
         assert_eq!(
             hex::encode(&parameters.KE3),
-            hex::encode(client_login_finish_result.message.serialize()?)
+            hex::encode(client_login_finish_result.message.serialize())
         );
         assert_eq!(
             hex::encode(&parameters.export_key),
@@ -549,24 +691,40 @@ fn test_ke3() -> Result<(), ProtocolError> {
 #[test]
 fn test_server_login_finish() -> Result<(), ProtocolError> {
     for parameters in rfc_to_params!(TEST_VECTORS) {
-        let password_file_bytes = get_password_file_bytes(&parameters)?;
+        let server_setup = ServerSetup::<Ristretto255Sha512NoSlowHash>::deserialize(
+            &[
+                &parameters.oprf_seed[..],
+                &parameters.server_private_key[..],
+                &parameters.dummy_private_key[..],
+            ]
+            .concat(),
+        )?;
 
-        let mut server_private_keyshare_and_nonce_rng =
-            CycleRng::new([parameters.server_private_keyshare, parameters.server_nonce].concat());
+        let record = ServerRegistration::<Ristretto255Sha512NoSlowHash>::deserialize(
+            &get_password_file_bytes(&parameters)?[..],
+        )?;
+
+        let mut server_private_keyshare_and_nonce_rng = CycleRng::new(
+            [
+                parameters.masking_nonce,
+                parameters.server_private_keyshare,
+                parameters.server_nonce,
+            ]
+            .concat(),
+        );
         let server_login_start_result = ServerLogin::<Ristretto255Sha512NoSlowHash>::start(
             &mut server_private_keyshare_and_nonce_rng,
-            ServerRegistration::deserialize(&password_file_bytes[..]).unwrap(),
-            &Key::from_bytes(&parameters.server_private_key[..]).unwrap(),
+            &server_setup,
+            Some(record),
             CredentialRequest::<Ristretto255Sha512NoSlowHash>::deserialize(&parameters.KE1[..])
                 .unwrap(),
-            if parameters.envelope_mode == EnvelopeMode::CustomIdentifier {
-                ServerLoginStartParameters::WithInfoAndIdentifiers(
-                    parameters.server_info.to_vec(),
-                    parameters.client_identity,
-                    parameters.server_identity,
-                )
-            } else {
-                ServerLoginStartParameters::WithInfo(parameters.server_info.to_vec())
+            &parameters.credential_identifier,
+            match parse_identifiers(parameters.client_identity, parameters.server_identity) {
+                None => ServerLoginStartParameters::WithContext(parameters.context.to_vec()),
+                Some(ids) => ServerLoginStartParameters::WithContextAndIdentifiers(
+                    parameters.context.to_vec(),
+                    ids,
+                ),
             },
         )?;
 
@@ -581,3 +739,47 @@ fn test_server_login_finish() -> Result<(), ProtocolError> {
     }
     Ok(())
 }
+
+#[test]
+fn test_fake_vectors() -> Result<(), ProtocolError> {
+    for parameters in rfc_to_params!(FAKE_TEST_VECTORS) {
+        let server_setup = ServerSetup::<Ristretto255Sha512NoSlowHash>::deserialize(
+            &[
+                &parameters.oprf_seed[..],
+                &parameters.server_private_key[..],
+                &parameters.dummy_private_key[..],
+            ]
+            .concat(),
+        )?;
+
+        let mut server_private_keyshare_and_nonce_rng = CycleRng::new(
+            [
+                parameters.dummy_masking_key,
+                parameters.masking_nonce,
+                parameters.server_private_keyshare,
+                parameters.server_nonce,
+            ]
+            .concat(),
+        );
+        let server_login_start_result = ServerLogin::<Ristretto255Sha512NoSlowHash>::start(
+            &mut server_private_keyshare_and_nonce_rng,
+            &server_setup,
+            None,
+            CredentialRequest::<Ristretto255Sha512NoSlowHash>::deserialize(&parameters.KE1[..])
+                .unwrap(),
+            &parameters.credential_identifier,
+            match parse_identifiers(parameters.client_identity, parameters.server_identity) {
+                None => ServerLoginStartParameters::WithContext(parameters.context.to_vec()),
+                Some(ids) => ServerLoginStartParameters::WithContextAndIdentifiers(
+                    parameters.context.to_vec(),
+                    ids,
+                ),
+            },
+        )?;
+        assert_eq!(
+            hex::encode(&parameters.KE2),
+            hex::encode(server_login_start_result.message.serialize())
+        );
+    }
+    Ok(())
+}

src/tests/voprf_test_vectors.rs

@@ -21,7 +21,7 @@ struct VOPRFTestVectorParameters {
 
 // Taken from https://github.com/cfrg/draft-irtf-cfrg-voprf/blob/master/draft-irtf-cfrg-voprf.md
 // in base mode
-static OPRF_RISTRETTO255_SHA512: &'static [&str] = &[
+static OPRF_RISTRETTO255_SHA512: &[&str] = &[
     r#"
     {
         "sksm": "758cbac0e1eb4265d80f6e6489d9a74d788f7ddeda67d7fb3c08b08f44bda30a",
@@ -45,25 +45,23 @@ static OPRF_RISTRETTO255_SHA512: &'static [&str] = &[
 ];
 
 fn decode(values: &Value, key: &str) -> Option<Vec<u8>> {
-    values[key]
-        .as_str()
-        .and_then(|s| hex::decode(&s.to_string()).ok())
+    values[key].as_str().and_then(|s| hex::decode(s).ok())
 }
 
 fn populate_test_vectors(values: &Value) -> VOPRFTestVectorParameters {
     VOPRFTestVectorParameters {
-        sksm: decode(&values, "sksm").unwrap(),
-        input: decode(&values, "input").unwrap(),
-        blind: decode(&values, "blind").unwrap(),
-        blinded_element: decode(&values, "blinded_element").unwrap(),
-        evaluation_element: decode(&values, "evaluation_element").unwrap(),
-        output: decode(&values, "output").unwrap(),
+        sksm: decode(values, "sksm").unwrap(),
+        input: decode(values, "input").unwrap(),
+        blind: decode(values, "blind").unwrap(),
+        blinded_element: decode(values, "blinded_element").unwrap(),
+        evaluation_element: decode(values, "evaluation_element").unwrap(),
+        output: decode(values, "output").unwrap(),
     }
 }
 
 // Tests input -> blind, blinded_element
 #[test]
-fn test_blind() -> Result<(), ProtocolError> {
+fn test_blind() -> Result<(), PakeError> {
     for tv in OPRF_RISTRETTO255_SHA512 {
         let parameters = populate_test_vectors(&serde_json::from_str(tv).unwrap());
         let mut rng = CycleRng::new(parameters.blind.to_vec());
@@ -106,7 +104,7 @@ fn test_evaluate() -> Result<(), PakeError> {
 
 // Tests input, blind, evaluation_element -> output
 #[test]
-fn test_finalize() -> Result<(), ProtocolError> {
+fn test_finalize() -> Result<(), PakeError> {
     for tv in OPRF_RISTRETTO255_SHA512 {
         let parameters = populate_test_vectors(&serde_json::from_str(tv).unwrap());
 
@@ -116,7 +114,7 @@ fn test_finalize() -> Result<(), ProtocolError> {
             RistrettoPoint::from_element_slice(GenericArray::from_slice(
                 &parameters.evaluation_element,
             ))?,
-        )?;
+        );
 
         assert_eq!(&parameters.output, &output.to_vec());
     }