Remove scrypt

.github/workflows/main.yml

@@ -70,7 +70,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: hecrj/setup-rust-action@v1
-      - run: cargo test --verbose --features scrypt,argon --no-default-features --features ${{ matrix.backend_feature }}
+      - run: cargo test --verbose --features slow-hash --no-default-features --features ${{ matrix.backend_feature }}
 
   serde-test:
     name: Test on ${{ matrix.target }} with serde support

Cargo.lock

@@ -624,7 +624,6 @@ dependencies = [
  "proptest",
  "rand 0.8.3",
  "rustyline",
- "scrypt",
  "serde",
  "serde_json",
  "sha2",
@@ -644,15 +643,6 @@ dependencies = [
  "subtle",
 ]
 
-[[package]]
-name = "pbkdf2"
-version = "0.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b3b8c0d71734018084da0c0354193a5edfb81b20d2d57a92c5b154aefc554a4a"
-dependencies = [
- "crypto-mac 0.10.0",
-]
-
 [[package]]
 name = "plotters"
 version = "0.3.0"
@@ -954,15 +944,6 @@ version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
 
-[[package]]
-name = "salsa20"
-version = "0.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "399f290ffc409596022fce5ea5d4138184be4784f2b28c62c59f0d8389059a15"
-dependencies = [
- "cipher",
-]
-
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -978,22 +959,6 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
-[[package]]
-name = "scrypt"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8da492dab03f925d977776a0b7233d7b934d6dc2b94faead48928e2e9bacedb9"
-dependencies = [
- "base64",
- "hmac",
- "pbkdf2",
- "rand 0.7.3",
- "rand_core 0.5.1",
- "salsa20",
- "sha2",
- "subtle",
-]
-
 [[package]]
 name = "semver"
 version = "0.9.0"

Cargo.toml

@@ -11,7 +11,7 @@ readme = "README.md"
 
 [features]
 default = ["u64_backend", "serialize"]
-argon = ["argon2"]
+slow-hash = ["argon2"]
 bench = []
 u64_backend = ["curve25519-dalek/u64_backend"]
 u32_backend = ["curve25519-dalek/u32_backend"]
@@ -28,7 +28,6 @@ generic-bytes = { version = "0.1.0" }
 hkdf = "0.10.0"
 hmac = "0.10.1"
 rand = "0.8"
-scrypt = { version = "0.5.0", optional = true }
 serde = { version = "1", optional = true }
 subtle = { version = "2.3.0", default-features = false }
 thiserror = "1.0.22"

src/lib.rs

@@ -32,8 +32,8 @@
 //! 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 `scrypt` feature. See more details in the [features](#features) section.
+//! 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 creating a `ServerSetup` object:
@@ -718,16 +718,13 @@
 //!
 //! # Features
 //!
-//! - The `scrypt` feature, when enabled, introduces a dependency on `scrypt` and implements the `SlowHash` trait for `scrypt`
+//! - 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 `argon` feature, when enabled, introduces a dependency on `argon2` and implements the `SlowHash` trait for `argon2`
-//! with default parameters. This is an alternative to `scrypt`.
-//!
 //! - The `serialize` feature, enabled by default, provides convenience functions for serializing and deserializing with
 //! [serde](https://serde.rs/).
 //!

src/slow_hash.rs

@@ -7,7 +7,7 @@
 
 use crate::{errors::InternalPakeError, hash::Hash};
 use digest::Digest;
-#[cfg(any(feature = "argon", feature = "scrypt"))]
+#[cfg(feature = "slow-hash")]
 use generic_array::typenum::Unsigned;
 use generic_array::GenericArray;
 
@@ -30,29 +30,7 @@ impl<D: Hash> SlowHash<D> for NoOpHash {
     }
 }
 
-#[cfg(feature = "scrypt")]
-const DEFAULT_SCRYPT_LOG_N: u8 = 15u8;
-#[cfg(feature = "scrypt")]
-const DEFAULT_SCRYPT_R: u32 = 8u32;
-#[cfg(feature = "scrypt")]
-const DEFAULT_SCRYPT_P: u32 = 1u32;
-
-#[cfg(feature = "scrypt")]
-impl<D: Hash> SlowHash<D> for scrypt::ScryptParams {
-    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 mut output = vec![0u8; <D as Digest>::OutputSize::to_usize()];
-        scrypt::scrypt(&input, &[], &params, &mut output)
-            .map_err(|_| InternalPakeError::SlowHashError)?;
-        Ok(output)
-    }
-}
-
-#[cfg(feature = "argon")]
+#[cfg(feature = "slow-hash")]
 impl<D: Hash> SlowHash<D> for argon2::Argon2<'_> {
     fn hash(
         input: GenericArray<u8, <D as Digest>::OutputSize>,