Updating envelope structure to support two fixed modes (#108)

* Moving id_u and id_s from ClientLoginStartParameters to ClientLoginFinishParameters

* Updating envelope format to support two fixed modes

src/serialization/mod.rs

@@ -5,26 +5,6 @@
 
 use crate::errors::PakeError;
 
-#[derive(Copy, Clone, Eq, Hash, PartialEq)]
-pub enum CredentialType {
-    SkU,
-    PkU,
-    PkS,
-    IdU,
-    IdS,
-}
-
-pub(crate) fn u8_to_credential_type(x: u8) -> Option<CredentialType> {
-    match x {
-        1 => Some(CredentialType::SkU),
-        2 => Some(CredentialType::PkU),
-        3 => Some(CredentialType::PkS),
-        4 => Some(CredentialType::IdU),
-        5 => Some(CredentialType::IdS),
-        _ => None,
-    }
-}
-
 // Corresponds to the I2OSP() function from RFC8017
 pub(crate) fn i2osp(input: usize, length: usize) -> Vec<u8> {
     if length <= std::mem::size_of::<usize>() {

src/serialization/tests.rs

@@ -5,7 +5,7 @@
 
 use crate::{
     ciphersuite::CipherSuite,
-    envelope::Envelope,
+    envelope::{Envelope, InnerEnvelopeMode},
     group::Group,
     key_exchange::{
         traits::{KeyExchange, ToBytes},
@@ -34,7 +34,6 @@ impl CipherSuite for Default {
     type SlowHash = crate::slow_hash::NoOpHash;
 }
 
-const MAX_ID_LENGTH: usize = 10;
 const MAX_INFO_LENGTH: usize = 10;
 
 fn random_ristretto_point() -> RistrettoPoint {
@@ -80,6 +79,7 @@ fn server_registration_roundtrip() {
 
     // Construct a mock envelope
     let mut mock_envelope_bytes = Vec::new();
+    mock_envelope_bytes.extend_from_slice(&[0; 1]); // mode = 0
     mock_envelope_bytes.extend_from_slice(&[0; NONCE_LEN]); // empty nonce
     mock_envelope_bytes.extend_from_slice(&[0, 0]); // empty ciphertext
     mock_envelope_bytes.extend_from_slice(&[0, 0]); // empty auth_data
@@ -121,7 +121,6 @@ fn register_second_message_roundtrip() {
     let mut rng = OsRng;
     let skp = Default::generate_random_keypair(&mut rng).unwrap();
     let pubkey_bytes = skp.public().to_arr();
-    let credential_types = [1, 1, 1, 3];
 
     let beta_length: usize = beta_bytes.len();
     let pubkey_length: usize = pubkey_bytes.len();
@@ -131,7 +130,6 @@ fn register_second_message_roundtrip() {
     input.extend_from_slice(beta_bytes.as_slice());
     input.extend_from_slice(&pubkey_length.to_be_bytes()[std::mem::size_of::<usize>() - 2..]);
     input.extend_from_slice(&pubkey_bytes.as_slice());
-    input.extend_from_slice(&credential_types);
 
     let r2 = RegistrationResponse::<RistrettoPoint>::deserialize(input.as_slice()).unwrap();
     let r2_bytes = r2.serialize();
@@ -150,8 +148,14 @@ fn register_third_message_roundtrip() {
     let mut msg = [0u8; 32];
     rng.fill_bytes(&mut msg);
 
-    let (envelope, _) =
-        Envelope::<sha2::Sha256>::seal_raw(&key, &msg, &pubkey_bytes, &mut rng).unwrap();
+    let (envelope, _) = Envelope::<sha2::Sha256>::seal_raw(
+        &mut rng,
+        &key,
+        &msg,
+        &pubkey_bytes,
+        InnerEnvelopeMode::Base,
+    )
+    .unwrap();
     let envelope_bytes = envelope.serialize();
 
     let pubkey_length: usize = pubkey_bytes.len();
@@ -206,6 +210,7 @@ fn login_second_message_roundtrip() {
     let mut rng = OsRng;
     let skp = Default::generate_random_keypair(&mut rng).unwrap();
     let pubkey_bytes = skp.public().to_arr();
+    let pubkey_length: usize = pubkey_bytes.len();
 
     let mut key = [0u8; 32];
     rng.fill_bytes(&mut key);
@@ -213,8 +218,14 @@ fn login_second_message_roundtrip() {
     let mut msg = [0u8; 32];
     rng.fill_bytes(&mut msg);
 
-    let (envelope, _) =
-        Envelope::<sha2::Sha256>::seal_raw(&key, &msg, &pubkey_bytes, &mut rng).unwrap();
+    let (envelope, _) = Envelope::<sha2::Sha256>::seal_raw(
+        &mut rng,
+        &key,
+        &msg,
+        &pubkey_bytes,
+        InnerEnvelopeMode::Base,
+    )
+    .unwrap();
 
     let server_e_kp = Default::generate_random_keypair(&mut rng).unwrap();
     let mut mac = [0u8; 32];
@@ -239,6 +250,8 @@ fn login_second_message_roundtrip() {
     let mut input = Vec::new();
     input.extend_from_slice(&pt_bytes.len().to_be_bytes()[std::mem::size_of::<usize>() - 2..]);
     input.extend_from_slice(pt_bytes.as_slice());
+    input.extend_from_slice(&pubkey_length.to_be_bytes()[std::mem::size_of::<usize>() - 2..]);
+    input.extend_from_slice(&pubkey_bytes.as_slice());
     input.extend_from_slice(&envelope.serialize());
     input.extend_from_slice(&ke2m[..]);
 
@@ -273,13 +286,6 @@ fn login_third_message_roundtrip() {
 fn client_login_roundtrip() {
     let pw = b"hunter2";
     let mut rng = OsRng;
-    let id_u_length: usize = rng.gen_range(0, MAX_ID_LENGTH);
-    let id_s_length: usize = rng.gen_range(0, MAX_ID_LENGTH);
-    let mut id_u = [0u8; MAX_ID_LENGTH];
-    rng.fill_bytes(&mut id_u);
-    let mut id_s = [0u8; MAX_ID_LENGTH];
-    rng.fill_bytes(&mut id_s);
-
     let sc = <RistrettoPoint as Group>::random_scalar(&mut rng);
 
     let client_e_kp = Default::generate_random_keypair(&mut rng).unwrap();
@@ -291,10 +297,8 @@ fn client_login_roundtrip() {
     hasher.update(l1_data);
     let hashed_l1 = hasher.finalize();
 
-    // serialization order: id_u, id_s, scalar, password, ke1_state
+    // serialization order: scalar, password, ke1_state
     let bytes: Vec<u8> = [
-        &serialize(&id_u[..id_u_length], 2)[..],
-        &serialize(&id_s[..id_s_length], 2)[..],
         &sc.as_bytes()[..],
         &pw[..],
         client_e_kp.public(),