diff options
| -rw-r--r-- | src/block.rs | 10 | ||||
| -rw-r--r-- | src/lib.rs | 26 |
2 files changed, 19 insertions, 17 deletions
diff --git a/src/block.rs b/src/block.rs index e1140e7..2b7907a 100644 --- a/src/block.rs +++ b/src/block.rs @@ -94,6 +94,16 @@ impl Block { result } + /// Pad the block to full length. + /// + /// Unlike [`pad`], this function takes the length in bytes. + pub fn pad_bytes(&self, length: u8) -> Block { + assert!(length <= 15); + let mut result = *self; + result[length as usize] = 0x80; + result + } + /// Clip the block by setting all bits beyond the given length to 0. pub fn clip(&self, length: usize) -> Block { match length { @@ -688,16 +688,6 @@ fn cipher_aez_core<A: AsRef<[u8]>, T: IntoIterator<Item = A>>( blocks.set_m_y(c_y); } -fn pad_to_blocks(value: &[u8]) -> impl Iterator<Item = Block> { - value.chunks(16).map(|chunk| { - if chunk.len() == 16 { - Block::from_slice(chunk) - } else { - Block::from_slice(chunk).pad(chunk.len() * 8) - } - }) -} - fn aez_hash<A: AsRef<[u8]>, T: IntoIterator<Item = A>>(aez: &Aez, tweaks: T) -> Block { let mut hash = Block::null(); for (i, tweak) in tweaks.into_iter().enumerate() { @@ -716,15 +706,17 @@ fn aez_hash<A: AsRef<[u8]>, T: IntoIterator<Item = A>>(aez: &Aez, tweaks: T) -> hash = hash ^ ej.eval(Block::from_slice(chunk)); } } else { - let blocks = pad_to_blocks(tweak); - for (l, chunk) in blocks.enumerate() { + let blocks = tweak.chunks_exact(16); + let remainder = blocks.remainder(); + + for chunk in blocks { ej.advance(); - if l == tweak.len() / 16 { - hash = hash ^ e(j.try_into().unwrap(), 0, aez, chunk); - } else { - hash = hash ^ ej.eval(chunk); - } + hash = hash ^ ej.eval(Block::from_slice(chunk)); } + + ej.advance(); + let chunk = Block::from_slice(remainder).pad_bytes(remainder.len() as u8); + hash = hash ^ e(j.try_into().unwrap(), 0, aez, chunk); } } hash |