dev(ciphers): move blake2b.rs and incorrect_hmac_blake2b.rs to dedicated hash_functions directory

ciphers/src/subtle/hash_functions/blake2b.rs

@@ -33,6 +33,7 @@ pub const OUT_MAX: usize = OUT_LEN;
 /// Hashes the given `data` with the [Blake2bMac] hash function under the given `key`.
 /// The both the length of the output the length of the key 32 bytes (or 256 bits).  
 ///
+/// TODO: Adapt example
 /// # Examples
 ///
 ///```rust

ciphers/src/subtle/hash_functions/incorrect_hmac_blake2b.rs

@@ -1,10 +1,11 @@
 use anyhow::ensure;
 use zeroize::Zeroizing;
-
+use rosenpass_cipher_traits::KeyedHash;
 use rosenpass_constant_time::xor;
 use rosenpass_to::{ops::copy_slice, with_destination, To};
 
-use crate::subtle::blake2b;
+use crate::subtle::hash_functions::blake2b;
+use crate::subtle::hash_functions::infer_keyed_hash::InferKeyedHash;
 
 /// The key length, 32 bytes or 256 bits.
 pub const KEY_LEN: usize = 32;
@@ -65,3 +66,16 @@ pub fn hash<'a>(key: &'a [u8], data: &'a [u8]) -> impl To<[u8], anyhow::Result<(
         Ok(())
     })
 }
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Blake2bCore;
+
+impl KeyedHash<32, 32> for Blake2bCore {
+    type Error = anyhow::Error;
+
+    fn keyed_hash(key: &[u8; 32], data: &[u8], out: &mut [u8; 32]) -> Result<(), Self::Error> {
+        hash(key, data).to(out)
+    }
+}
+
+pub type Blake2b = InferKeyedHash<Blake2bCore, 32, 32>;

ciphers/src/subtle/hash_functions/mod.rs

@@ -1,2 +1,4 @@
+pub mod blake2b;
+pub mod incorrect_hmac_blake2b;
 pub mod keyed_shake256;
 mod infer_keyed_hash;

ciphers/src/subtle/mod.rs

@@ -4,13 +4,11 @@
 /// - [chacha20poly1305_ietf_libcrux]: The Chacha20Poly1305 AEAD as implemented in [libcrux](https://github.com/cryspen/libcrux) (only used when the feature `experiment_libcrux` is enabled).
 /// - [incorrect_hmac_blake2b]: An (incorrect) hmac based on [blake2b].
 /// - [xchacha20poly1305_ietf] The Chacha20Poly1305 AEAD as implemented in [RustCrypto](https://crates.io/crates/chacha20poly1305)
-pub mod blake2b;
 #[cfg(not(feature = "experiment_libcrux"))]
 pub mod chacha20poly1305_ietf;
 #[cfg(feature = "experiment_libcrux")]
 pub mod chacha20poly1305_ietf_libcrux;
-pub mod incorrect_hmac_blake2b;
 pub mod xchacha20poly1305_ietf;
-pub mod hash_functions;
+mod hash_functions;
 
-pub use hash_functions::{keyed_shake256}; 
+pub use hash_functions::{blake2b, incorrect_hmac_blake2b, keyed_shake256};