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https://github.com/BLAKE3-team/BLAKE3
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add the reference implementation
This commit is contained in:
Jack O'Connor
parent
4d0d2ccd99
commit
2030966062
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[package]
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name = "reference_impl"
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version = "0.0.0"
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edition = "2018"
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[lib]
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name = "reference_impl"
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path = "reference_impl.rs"
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This implementation is a single file with no dependencies. It's designed
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to be short and simple, and it is not optimized for performance.
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use core::cmp::min;
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use core::convert::TryInto;
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const OUT_LEN: usize = 32;
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const KEY_LEN: usize = 32;
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const BLOCK_LEN: usize = 64;
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const CHUNK_LEN: usize = 2048;
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const ROUNDS: usize = 7;
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const CHUNK_START: u32 = 1 << 0;
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const CHUNK_END: u32 = 1 << 1;
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const PARENT: u32 = 1 << 2;
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const ROOT: u32 = 1 << 3;
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const KEYED_HASH: u32 = 1 << 4;
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const DERIVE_KEY: u32 = 1 << 5;
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const IV: [u32; 8] = [
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0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19,
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];
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const MSG_SCHEDULE: [[usize; 16]; ROUNDS] = [
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[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15],
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[14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3],
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[11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4],
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[7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8],
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[9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13],
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[2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9],
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[12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11],
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];
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// The mixing function, G, which mixes either a column or a diagonal.
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fn g(state: &mut [u32; 16], a: usize, b: usize, c: usize, d: usize, mx: u32, my: u32) {
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state[a] = state[a].wrapping_add(state[b]).wrapping_add(mx);
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state[d] = (state[d] ^ state[a]).rotate_right(16);
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state[c] = state[c].wrapping_add(state[d]);
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state[b] = (state[b] ^ state[c]).rotate_right(12);
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state[a] = state[a].wrapping_add(state[b]).wrapping_add(my);
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state[d] = (state[d] ^ state[a]).rotate_right(8);
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state[c] = state[c].wrapping_add(state[d]);
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state[b] = (state[b] ^ state[c]).rotate_right(7);
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}
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fn round(state: &mut [u32; 16], m: &[u32; 16], schedule: &[usize; 16]) {
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// Mix the columns.
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g(state, 0, 4, 8, 12, m[schedule[0]], m[schedule[1]]);
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g(state, 1, 5, 9, 13, m[schedule[2]], m[schedule[3]]);
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g(state, 2, 6, 10, 14, m[schedule[4]], m[schedule[5]]);
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g(state, 3, 7, 11, 15, m[schedule[6]], m[schedule[7]]);
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// Mix the diagonals.
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g(state, 0, 5, 10, 15, m[schedule[8]], m[schedule[9]]);
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g(state, 1, 6, 11, 12, m[schedule[10]], m[schedule[11]]);
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g(state, 2, 7, 8, 13, m[schedule[12]], m[schedule[13]]);
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g(state, 3, 4, 9, 14, m[schedule[14]], m[schedule[15]]);
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}
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fn compress(
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chaining_value: &[u32; 8],
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block_words: &[u32; 16],
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offset: u64,
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block_len: u32,
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flags: u32,
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) -> [u32; 16] {
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let mut state = [
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chaining_value[0],
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chaining_value[1],
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chaining_value[2],
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chaining_value[3],
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chaining_value[4],
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chaining_value[5],
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chaining_value[6],
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chaining_value[7],
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IV[0],
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IV[1],
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IV[2],
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IV[3],
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offset as u32,
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(offset >> 32) as u32,
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block_len,
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flags,
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];
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for r in 0..ROUNDS {
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round(&mut state, &block_words, &MSG_SCHEDULE[r]);
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}
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for i in 0..8 {
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state[i] ^= state[i + 8];
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state[i + 8] ^= chaining_value[i];
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}
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state
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}
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fn first_8_words(compression_output: [u32; 16]) -> [u32; 8] {
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compression_output[0..8].try_into().unwrap()
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}
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fn words_from_litte_endian_bytes(bytes: &[u8], words: &mut [u32]) {
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for (bytes_block, word) in bytes.chunks_exact(4).zip(words.iter_mut()) {
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*word = u32::from_le_bytes(bytes_block.try_into().unwrap());
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}
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}
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// Each chunk or parent node can produce either an 8-word chaining value or, by
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// setting the ROOT flag, any number of final output bytes. The Output struct
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// captures the state just prior to choosing between those two possibilities.
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struct Output {
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input_chaining_value: [u32; 8],
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block_words: [u32; 16],
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offset: u64,
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block_len: u32,
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flags: u32,
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}
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impl Output {
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fn chaining_value(&self) -> [u32; 8] {
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first_8_words(compress(
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&self.input_chaining_value,
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&self.block_words,
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self.offset,
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self.block_len,
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self.flags,
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))
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}
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fn root_output_bytes(&self, out_slice: &mut [u8]) {
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let mut offset = 0;
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for out_block in out_slice.chunks_mut(2 * OUT_LEN) {
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let words = compress(
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&self.input_chaining_value,
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&self.block_words,
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offset,
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self.block_len,
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self.flags | ROOT,
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);
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// The output length might not be a multiple of 4.
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for (word, out_word) in words.iter().zip(out_block.chunks_mut(4)) {
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out_word.copy_from_slice(&word.to_le_bytes()[..out_word.len()]);
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}
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offset += 2 * OUT_LEN as u64;
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}
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}
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}
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struct ChunkState {
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chaining_value: [u32; 8],
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offset: u64,
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block: [u8; BLOCK_LEN],
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block_len: u8,
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blocks_compressed: u8,
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flags: u32,
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}
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impl ChunkState {
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fn new(key: &[u32; 8], offset: u64, flags: u32) -> Self {
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Self {
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chaining_value: *key,
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offset,
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block: [0; BLOCK_LEN],
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block_len: 0,
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blocks_compressed: 0,
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flags,
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}
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}
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fn len(&self) -> usize {
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BLOCK_LEN * self.blocks_compressed as usize + self.block_len as usize
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}
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fn start_flag(&self) -> u32 {
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if self.blocks_compressed == 0 {
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CHUNK_START
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} else {
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0
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}
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}
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fn update(&mut self, mut input: &[u8]) {
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while !input.is_empty() {
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if self.block_len as usize == BLOCK_LEN {
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let mut block_words = [0; 16];
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words_from_litte_endian_bytes(&self.block, &mut block_words);
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self.chaining_value = first_8_words(compress(
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&self.chaining_value,
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&block_words,
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self.offset,
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BLOCK_LEN as u32,
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self.flags | self.start_flag(),
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));
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self.blocks_compressed += 1;
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self.block = [0; BLOCK_LEN];
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self.block_len = 0;
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}
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let want = BLOCK_LEN - self.block_len as usize;
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let take = min(want, input.len());
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self.block[self.block_len as usize..][..take].copy_from_slice(&input[..take]);
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self.block_len += take as u8;
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input = &input[take..];
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}
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}
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fn output(&self) -> Output {
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let mut block_words = [0; 16];
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words_from_litte_endian_bytes(&self.block, &mut block_words);
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Output {
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input_chaining_value: self.chaining_value,
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block_words,
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block_len: self.block_len as u32,
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offset: self.offset,
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flags: self.flags | self.start_flag() | CHUNK_END,
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}
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}
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}
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fn parent_output(
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left_child_cv: &[u32; 8],
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right_child_cv: &[u32; 8],
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key: &[u32; 8],
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flags: u32,
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) -> Output {
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let mut block_words = [0; 16];
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block_words[..8].copy_from_slice(left_child_cv);
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block_words[8..].copy_from_slice(right_child_cv);
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Output {
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input_chaining_value: *key,
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block_words,
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offset: 0, // Always 0 for parent nodes.
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block_len: BLOCK_LEN as u32, // Always BLOCK_LEN (64) for parent nodes.
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flags: PARENT | flags,
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}
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}
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/// An incremental hasher that can accept any number of writes.
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pub struct Hasher {
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chunk_state: ChunkState,
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key: [u32; 8],
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subtree_stack: [[u32; 8]; 53], // Space for 53 subtree chaining values:
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subtree_stack_len: u8, // 2^53 * CHUNK_LEN = 2^64
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}
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impl Hasher {
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fn new_internal(key: &[u32; 8], flags: u32) -> Self {
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Self {
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chunk_state: ChunkState::new(key, 0, flags),
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key: *key,
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subtree_stack: [[0; 8]; 53],
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subtree_stack_len: 0,
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}
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}
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/// Construct a new `Hasher` for the default **hash** mode.
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pub fn new() -> Self {
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Self::new_internal(&IV, 0)
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}
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/// Construct a new `Hasher` for the **keyed_hash** mode.
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pub fn new_keyed(key: &[u8; KEY_LEN]) -> Self {
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let mut key_words = [0; 8];
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words_from_litte_endian_bytes(key, &mut key_words);
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Self::new_internal(&key_words, KEYED_HASH)
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}
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/// Construct a new `Hasher` for the **derive_key** mode.
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pub fn new_derive_key(key: &[u8; KEY_LEN]) -> Self {
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let mut key_words = [0; 8];
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words_from_litte_endian_bytes(key, &mut key_words);
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Self::new_internal(&key_words, DERIVE_KEY)
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}
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fn push_stack(&mut self, cv: &[u32; 8]) {
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self.subtree_stack[self.subtree_stack_len as usize] = *cv;
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self.subtree_stack_len += 1;
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}
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fn pop_stack(&mut self) -> [u32; 8] {
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self.subtree_stack_len -= 1;
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self.subtree_stack[self.subtree_stack_len as usize]
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}
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fn push_chunk_chaining_value(&mut self, mut cv: [u32; 8], total_bytes: u64) {
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// The new chunk chaining value might complete some subtrees along the
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// right edge of the growing tree. For each completed subtree, pop its
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// left child CV off the stack and compress a new parent CV. After as
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// many parent compressions as possible, push the new CV onto the
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// stack. The final length of the stack will be the count of 1 bits in
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// the total number of chunks or (equivalently) input bytes so far.
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let final_stack_len = total_bytes.count_ones() as u8;
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while self.subtree_stack_len >= final_stack_len {
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cv = parent_output(&self.pop_stack(), &cv, &self.key, self.chunk_state.flags)
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.chaining_value();
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}
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self.push_stack(&cv);
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}
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/// Add input to the hash state. This can be called any number of times.
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pub fn update(&mut self, mut input: &[u8]) {
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while !input.is_empty() {
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if self.chunk_state.len() == CHUNK_LEN {
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let chunk_cv = self.chunk_state.output().chaining_value();
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let new_chunk_offset = self.chunk_state.offset + CHUNK_LEN as u64;
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self.push_chunk_chaining_value(chunk_cv, new_chunk_offset);
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self.chunk_state =
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ChunkState::new(&self.key, new_chunk_offset, self.chunk_state.flags);
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}
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let want = CHUNK_LEN - self.chunk_state.len();
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let take = min(want, input.len());
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self.chunk_state.update(&input[..take]);
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input = &input[take..];
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}
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}
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/// Finalize the hash and write any number of output bytes.
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pub fn finalize(&self, out_slice: &mut [u8]) {
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// Starting with the Output from the current chunk, compute all the
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// parent chaining values along the right edge of the tree, until we
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// have the root Output.
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let mut output = self.chunk_state.output();
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let mut parent_nodes_remaining = self.subtree_stack_len as usize;
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while parent_nodes_remaining > 0 {
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parent_nodes_remaining -= 1;
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output = parent_output(
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&self.subtree_stack[parent_nodes_remaining],
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&output.chaining_value(),
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&self.key,
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self.chunk_state.flags,
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);
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}
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output.root_output_bytes(out_slice);
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}
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}
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