feat: add SHA-2 family of hash functions

DIRECTORY.md

@@ -55,7 +55,7 @@
     * [ROT13](https://github.com/TheAlgorithms/Rust/blob/master/src/ciphers/rot13.rs)
     * [RSA Cipher](https://github.com/TheAlgorithms/Rust/blob/master/src/ciphers/rsa_cipher.rs)
     * [Salsa](https://github.com/TheAlgorithms/Rust/blob/master/src/ciphers/salsa.rs)
-    * [SHA-256](https://github.com/TheAlgorithms/Rust/blob/master/src/ciphers/sha256.rs)
+    * [SHA-2](https://github.com/TheAlgorithms/Rust/blob/master/src/ciphers/sha2.rs)
     * [SHA-3](https://github.com/TheAlgorithms/Rust/blob/master/src/ciphers/sha3.rs)
     * [Tea](https://github.com/TheAlgorithms/Rust/blob/master/src/ciphers/tea.rs)
     * [Theoretical ROT13](https://github.com/TheAlgorithms/Rust/blob/master/src/ciphers/theoretical_rot13.rs)

src/ciphers/hashing_traits.rs

@@ -1,17 +1,17 @@
 pub trait Hasher<const DIGEST_BYTES: usize> {
-    /// return a new instance with default parameters
+    /// Return a new instance with default parameters.
     fn new_default() -> Self;
 
-    /// Add new data
+    /// Add new data.
     fn update(&mut self, data: &[u8]);
 
-    /// Returns the hash of current data. If it is necessary does finalization
-    /// work on the instance, thus it may no longer make sense to do `update`
+    /// Returns the hash of current data. If necessary does finalization work
+    /// on the instance, thus it may no longer make sense to call `update`
     /// after calling this.
     fn get_hash(&mut self) -> [u8; DIGEST_BYTES];
 }
 
-/// HMAC based on RFC2104, applicable to many cryptographic hash functions
+/// HMAC based on RFC 2104, applicable to many cryptographic hash functions.
 pub struct HMAC<const KEY_BYTES: usize, const DIGEST_BYTES: usize, H: Hasher<DIGEST_BYTES>> {
     pub inner_internal_state: H,
     pub outer_internal_state: H,
@@ -27,25 +27,24 @@ impl<const KEY_BYTES: usize, const DIGEST_BYTES: usize, H: Hasher<DIGEST_BYTES>>
         }
     }
 
-    /// Note that `key` must be no longer than `KEY_BYTES`. According to RFC,
-    /// if it is so, you should replace it with its hash. We do not do this
-    /// automatically due to fear of `DIGEST_BYTES` not being the same as
-    /// `KEY_BYTES` or even being longer than it
+    /// Note that `key` must be no longer than `KEY_BYTES`. According to the
+    /// RFC, if it is so, you should replace it with its hash. We do not do
+    /// this automatically due to fear of `DIGEST_BYTES` not being the same as
+    /// `KEY_BYTES` or even being longer than it.
     pub fn add_key(&mut self, key: &[u8]) -> Result<(), &'static str> {
         match key.len().cmp(&KEY_BYTES) {
             std::cmp::Ordering::Less | std::cmp::Ordering::Equal => {
                 let mut tmp_key = [0u8; KEY_BYTES];
                 for (d, s) in tmp_key.iter_mut().zip(key.iter()) {
                     *d = *s;
                 }
-                // key ^ 0x363636.. should be used as inner key
+                // key XOR 0x363636… is the inner key
                 for b in tmp_key.iter_mut() {
                     *b ^= 0x36;
                 }
                 self.inner_internal_state.update(&tmp_key);
-                // key ^ 0x5c5c5c.. should be used as outer key, but the key is
-                // already XORed with 0x363636.. , so it must now be XORed with
-                // 0x6a6a6a..
+                // key XOR 0x5c5c5c… is the outer key; the key is already
+                // XORed with 0x36, so XOR with 0x6a to get the net 0x5c.
                 for b in tmp_key.iter_mut() {
                     *b ^= 0x6a;
                 }
@@ -66,24 +65,3 @@ impl<const KEY_BYTES: usize, const DIGEST_BYTES: usize, H: Hasher<DIGEST_BYTES>>
         self.outer_internal_state.get_hash()
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::super::sha256::tests::get_hash_string;
-    use super::super::SHA256;
-    use super::HMAC;
-
-    #[test]
-    fn sha256_basic() {
-        // To test this, use the following command on linux:
-        // echo -n "Hello World" | openssl sha256 -hex -mac HMAC -macopt hexkey:"deadbeef"
-        let mut hmac: HMAC<64, 32, SHA256> = HMAC::new_default();
-        hmac.add_key(&[0xde, 0xad, 0xbe, 0xef]).unwrap();
-        hmac.update(b"Hello World");
-        let hash = hmac.finalize();
-        assert_eq!(
-            get_hash_string(&hash),
-            "f585fc4536e8e7f378437465b65b6c2eb79036409b18a7d28b6d4c46d3a156f8"
-        );
-    }
-}

src/ciphers/mod.rs

@@ -19,7 +19,7 @@ mod rail_fence;
 mod rot13;
 mod rsa_cipher;
 mod salsa;
-mod sha256;
+mod sha2;
 mod sha3;
 mod tea;
 mod theoretical_rot13;
@@ -41,8 +41,7 @@ pub use self::blake2b::blake2b;
 pub use self::caesar::caesar;
 pub use self::chacha::chacha20;
 pub use self::diffie_hellman::DiffieHellman;
-pub use self::hashing_traits::Hasher;
-pub use self::hashing_traits::HMAC;
+pub use self::hashing_traits::{Hasher, HMAC};
 pub use self::hill_cipher::HillCipher;
 pub use self::kernighan::kernighan;
 pub use self::morse_code::{decode, encode};
@@ -53,7 +52,7 @@ pub use self::rsa_cipher::{
     decrypt, decrypt_text, encrypt, encrypt_text, generate_keypair, PrivateKey, PublicKey,
 };
 pub use self::salsa::salsa20;
-pub use self::sha256::SHA256;
+pub use self::sha2::{sha224, sha256, sha384, sha512, sha512_224, sha512_256};
 pub use self::sha3::{sha3_224, sha3_256, sha3_384, sha3_512};
 pub use self::tea::{tea_decrypt, tea_encrypt};
 pub use self::theoretical_rot13::theoretical_rot13;