ocb3: use Ocb3 as the type name (#588)

Renames `AesOcb3` to `Ocb3`.

Unlike AES-GCM, AES-GCM-SIV, and AES-SIV, in which AES is the de facto
cipher for that mode, OCB is defined in a more cipher-agnostic way
similar to CCM or EAX modes (which, as it were, is reflected in our
choice of crate names).

This renames the type to reflect that, and as it were, match the crate
name as well.

ocb3/README.md

@@ -18,10 +18,10 @@ use aes::Aes128;
 use ocb3::{
     aead::{Aead, AeadCore, KeyInit, OsRng, generic_array::GenericArray},
     consts::U12,
-    AesOcb3,
+    Ocb3,
 };
 
-type Aes128Ocb3 = AesOcb3<Aes128, U12>;
+type Aes128Ocb3 = Ocb3<Aes128, U12>;
 
 let key = Aes128::generate_key(&mut OsRng);
 let cipher = Aes128Ocb3::new(&key);

ocb3/src/lib.rs

@@ -80,17 +80,14 @@ mod private {
     impl SealedNonceSize for consts::U12 {}
 }
 
-/// AES-OCB3: generic over an AES implementation, nonce size, and tag size.
-///
-/// WARNING: Unless absolutely necessary, prefer the aliases Aes128Ocb3 and
-/// Aes256Ocb3.
+/// OCB3: generic over a block cipher implementation, nonce size, and tag size.
 #[derive(Clone)]
-pub struct AesOcb3<Aes, NonceSize = U12, TagSize = U16>
+pub struct Ocb3<Cipher, NonceSize = U12, TagSize = U16>
 where
     NonceSize: self::NonceSize,
     TagSize: self::TagSize,
 {
-    cipher: Aes,
+    cipher: Cipher,
     nonce_size: PhantomData<NonceSize>,
     tag_size: PhantomData<TagSize>,
     // precomputed key-dependent variables
@@ -104,27 +101,27 @@ where
 type SumSize = U16;
 type Sum = GenericArray<u8, SumSize>;
 
-impl<Aes, NonceSize, TagSize> KeySizeUser for AesOcb3<Aes, NonceSize, TagSize>
+impl<Cipher, NonceSize, TagSize> KeySizeUser for Ocb3<Cipher, NonceSize, TagSize>
 where
-    Aes: KeySizeUser,
+    Cipher: KeySizeUser,
     TagSize: self::TagSize,
     NonceSize: self::NonceSize,
 {
-    type KeySize = Aes::KeySize;
+    type KeySize = Cipher::KeySize;
 }
 
-impl<Aes, NonceSize, TagSize> KeyInit for AesOcb3<Aes, NonceSize, TagSize>
+impl<Cipher, NonceSize, TagSize> KeyInit for Ocb3<Cipher, NonceSize, TagSize>
 where
-    Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt + KeyInit + BlockDecrypt,
+    Cipher: BlockSizeUser<BlockSize = U16> + BlockEncrypt + KeyInit + BlockDecrypt,
     TagSize: self::TagSize,
     NonceSize: self::NonceSize,
 {
     fn new(key: &aead::Key<Self>) -> Self {
-        Aes::new(key).into()
+        Cipher::new(key).into()
     }
 }
 
-impl<Aes, NonceSize, TagSize> AeadCore for AesOcb3<Aes, NonceSize, TagSize>
+impl<Cipher, NonceSize, TagSize> AeadCore for Ocb3<Cipher, NonceSize, TagSize>
 where
     NonceSize: self::NonceSize,
     TagSize: self::TagSize,
@@ -134,13 +131,13 @@ where
     type CiphertextOverhead = U0;
 }
 
-impl<Aes, NonceSize, TagSize> From<Aes> for AesOcb3<Aes, NonceSize, TagSize>
+impl<Cipher, NonceSize, TagSize> From<Cipher> for Ocb3<Cipher, NonceSize, TagSize>
 where
-    Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt + BlockDecrypt,
+    Cipher: BlockSizeUser<BlockSize = U16> + BlockEncrypt + BlockDecrypt,
     TagSize: self::TagSize,
     NonceSize: self::NonceSize,
 {
-    fn from(cipher: Aes) -> Self {
+    fn from(cipher: Cipher) -> Self {
         let (ll_star, ll_dollar, ll) = key_dependent_variables(&cipher);
 
         Self {
@@ -156,8 +153,8 @@ where
 
 /// Computes key-dependent variables defined in
 /// https://www.rfc-editor.org/rfc/rfc7253.html#section-4.1
-fn key_dependent_variables<Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt>(
-    cipher: &Aes,
+fn key_dependent_variables<Cipher: BlockSizeUser<BlockSize = U16> + BlockEncrypt>(
+    cipher: &Cipher,
 ) -> (Block, Block, [Block; L_TABLE_SIZE]) {
     let mut zeros = [0u8; 16];
     let ll_star = Block::from_mut_slice(&mut zeros);
@@ -174,9 +171,9 @@ fn key_dependent_variables<Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt>(
     (*ll_star, ll_dollar, ll)
 }
 
-impl<Aes, NonceSize, TagSize> AeadInPlace for AesOcb3<Aes, NonceSize, TagSize>
+impl<Cipher, NonceSize, TagSize> AeadInPlace for Ocb3<Cipher, NonceSize, TagSize>
 where
-    Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt + BlockDecrypt,
+    Cipher: BlockSizeUser<BlockSize = U16> + BlockEncrypt + BlockDecrypt,
     TagSize: self::TagSize,
     NonceSize: self::NonceSize,
 {
@@ -256,9 +253,9 @@ where
     }
 }
 
-impl<Aes, NonceSize, TagSize> AesOcb3<Aes, NonceSize, TagSize>
+impl<Cipher, NonceSize, TagSize> Ocb3<Cipher, NonceSize, TagSize>
 where
-    Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt + BlockDecrypt,
+    Cipher: BlockSizeUser<BlockSize = U16> + BlockEncrypt + BlockDecrypt,
     TagSize: self::TagSize,
     NonceSize: self::NonceSize,
 {
@@ -410,10 +407,10 @@ where
 ///
 /// Assumes a 96-bit nonce and 128-bit tag.
 fn nonce_dependent_variables<
-    Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt,
+    Cipher: BlockSizeUser<BlockSize = U16> + BlockEncrypt,
     NonceSize: self::NonceSize,
 >(
-    cipher: &Aes,
+    cipher: &Cipher,
     nn: &Nonce<NonceSize>,
     tag_len: u32,
 ) -> (usize, [u8; 24]) {
@@ -454,10 +451,10 @@ fn nonce_dependent_variables<
 ///
 /// Assumes a 96-bit nonce and 128-bit tag.
 fn initial_offset<
-    Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt,
+    Cipher: BlockSizeUser<BlockSize = U16> + BlockEncrypt,
     NonceSize: self::NonceSize,
 >(
-    cipher: &Aes,
+    cipher: &Cipher,
     nn: &Nonce<NonceSize>,
     tag_size: u32,
 ) -> Block {
@@ -471,9 +468,9 @@ fn initial_offset<
     offset.to_be_bytes().into()
 }
 
-impl<Aes, NonceSize, TagSize> AesOcb3<Aes, NonceSize, TagSize>
+impl<Cipher, NonceSize, TagSize> Ocb3<Cipher, NonceSize, TagSize>
 where
-    Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt,
+    Cipher: BlockSizeUser<BlockSize = U16> + BlockEncrypt,
     TagSize: self::TagSize,
     NonceSize: self::NonceSize,
 {

ocb3/tests/kats.rs

@@ -6,7 +6,7 @@ use aead::{
 };
 use aes::{Aes128, Aes192, Aes256};
 use hex_literal::hex;
-use ocb3::{AesOcb3, GenericArray};
+use ocb3::{GenericArray, Ocb3};
 
 // Test vectors from https://www.rfc-editor.org/rfc/rfc7253.html#appendix-A
 aead::new_test!(rfc7253_ocb_aes, "rfc7253_ocb_aes", Aes128Ocb3);
@@ -83,15 +83,15 @@ macro_rules! rfc7253_wider_variety {
 }
 
 // More types for testing
-type Aes192Ocb3 = AesOcb3<Aes192, U12>;
-type Aes128Ocb3Tag96 = AesOcb3<Aes128, U12, U12>;
-type Aes192Ocb3Tag96 = AesOcb3<Aes192, U12, U12>;
-type Aes256Ocb3Tag96 = AesOcb3<Aes256, U12, U12>;
-type Aes128Ocb3Tag64 = AesOcb3<Aes128, U12, U8>;
-type Aes192Ocb3Tag64 = AesOcb3<Aes192, U12, U8>;
-type Aes256Ocb3Tag64 = AesOcb3<Aes256, U12, U8>;
-type Aes128Ocb3 = AesOcb3<aes::Aes128, U12>;
-type Aes256Ocb3 = AesOcb3<aes::Aes256, U12>;
+type Aes192Ocb3 = Ocb3<Aes192, U12>;
+type Aes128Ocb3Tag96 = Ocb3<Aes128, U12, U12>;
+type Aes192Ocb3Tag96 = Ocb3<Aes192, U12, U12>;
+type Aes256Ocb3Tag96 = Ocb3<Aes256, U12, U12>;
+type Aes128Ocb3Tag64 = Ocb3<Aes128, U12, U8>;
+type Aes192Ocb3Tag64 = Ocb3<Aes192, U12, U8>;
+type Aes256Ocb3Tag64 = Ocb3<Aes256, U12, U8>;
+type Aes128Ocb3 = Ocb3<aes::Aes128, U12>;
+type Aes256Ocb3 = Ocb3<aes::Aes256, U12>;
 
 /// Test vectors from Page 18 of https://www.rfc-editor.org/rfc/rfc7253.html#appendix-A
 #[test]