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| 1 | +use belt_block::belt_block_raw; |
| 2 | +use core::fmt; |
| 3 | +use digest::{ |
| 4 | + HashMarker, Output, |
| 5 | + block_buffer::Eager, |
| 6 | + core_api::{ |
| 7 | + AlgorithmName, Block, BlockSizeUser, Buffer, BufferKindUser, FixedOutputCore, |
| 8 | + OutputSizeUser, Reset, UpdateCore, |
| 9 | + }, |
| 10 | + crypto_common::hazmat::{DeserializeStateError, SerializableState, SerializedState}, |
| 11 | + typenum::{U32, U64, Unsigned}, |
| 12 | +}; |
| 13 | + |
| 14 | +const H0: [u32; 8] = [ |
| 15 | + 0xC8BA94B1, 0x3BF5080A, 0x8E006D36, 0xE45D4A58, 0x9DFA0485, 0xACC7B61B, 0xC2722E25, 0x0DCEFD02, |
| 16 | +]; |
| 17 | + |
| 18 | +/// Core BelT hasher state. |
| 19 | +#[derive(Clone)] |
| 20 | +pub struct BeltHashCore { |
| 21 | + r: u128, |
| 22 | + s: [u32; 4], |
| 23 | + h: [u32; 8], |
| 24 | +} |
| 25 | + |
| 26 | +impl BeltHashCore { |
| 27 | + fn compress_block(&mut self, block: &Block<Self>) { |
| 28 | + let x1 = read_u32s(&block[..16]); |
| 29 | + let x2 = read_u32s(&block[16..]); |
| 30 | + let (t, h) = belt_compress(x1, x2, self.h); |
| 31 | + self.h = h; |
| 32 | + self.s = xor(self.s, t); |
| 33 | + } |
| 34 | +} |
| 35 | + |
| 36 | +impl HashMarker for BeltHashCore {} |
| 37 | + |
| 38 | +impl BlockSizeUser for BeltHashCore { |
| 39 | + type BlockSize = U32; |
| 40 | +} |
| 41 | + |
| 42 | +impl BufferKindUser for BeltHashCore { |
| 43 | + type BufferKind = Eager; |
| 44 | +} |
| 45 | + |
| 46 | +impl OutputSizeUser for BeltHashCore { |
| 47 | + type OutputSize = U32; |
| 48 | +} |
| 49 | + |
| 50 | +impl UpdateCore for BeltHashCore { |
| 51 | + #[inline] |
| 52 | + fn update_blocks(&mut self, blocks: &[Block<Self>]) { |
| 53 | + self.r = self.r.wrapping_add(blocks.len() as u128); |
| 54 | + for block in blocks { |
| 55 | + self.compress_block(block); |
| 56 | + } |
| 57 | + } |
| 58 | +} |
| 59 | + |
| 60 | +impl FixedOutputCore for BeltHashCore { |
| 61 | + #[inline] |
| 62 | + fn finalize_fixed_core(&mut self, buffer: &mut Buffer<Self>, out: &mut Output<Self>) { |
| 63 | + let pos = buffer.get_pos(); |
| 64 | + if pos != 0 { |
| 65 | + let block = buffer.pad_with_zeros(); |
| 66 | + self.compress_block(&block); |
| 67 | + } |
| 68 | + let bs = Self::BlockSize::USIZE as u128; |
| 69 | + let r = encode_r(8 * ((bs * self.r) + pos as u128)); |
| 70 | + let (_, y) = belt_compress(r, self.s, self.h); |
| 71 | + write_u32s(&y, out); |
| 72 | + } |
| 73 | +} |
| 74 | + |
| 75 | +impl Default for BeltHashCore { |
| 76 | + #[inline] |
| 77 | + fn default() -> Self { |
| 78 | + Self { |
| 79 | + r: 0, |
| 80 | + s: [0; 4], |
| 81 | + h: H0, |
| 82 | + } |
| 83 | + } |
| 84 | +} |
| 85 | + |
| 86 | +impl Reset for BeltHashCore { |
| 87 | + #[inline] |
| 88 | + fn reset(&mut self) { |
| 89 | + *self = Default::default(); |
| 90 | + } |
| 91 | +} |
| 92 | + |
| 93 | +impl AlgorithmName for BeltHashCore { |
| 94 | + fn write_alg_name(f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| 95 | + f.write_str("BeltHash") |
| 96 | + } |
| 97 | +} |
| 98 | + |
| 99 | +impl fmt::Debug for BeltHashCore { |
| 100 | + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| 101 | + f.write_str("BeltHashCore { ... }") |
| 102 | + } |
| 103 | +} |
| 104 | + |
| 105 | +impl Drop for BeltHashCore { |
| 106 | + fn drop(&mut self) { |
| 107 | + #[cfg(feature = "zeroize")] |
| 108 | + { |
| 109 | + use digest::zeroize::Zeroize; |
| 110 | + self.r.zeroize(); |
| 111 | + self.s.zeroize(); |
| 112 | + self.h.zeroize(); |
| 113 | + } |
| 114 | + } |
| 115 | +} |
| 116 | + |
| 117 | +#[cfg(feature = "zeroize")] |
| 118 | +impl digest::zeroize::ZeroizeOnDrop for BeltHashCore {} |
| 119 | + |
| 120 | +impl SerializableState for BeltHashCore { |
| 121 | + type SerializedStateSize = U64; |
| 122 | + |
| 123 | + fn serialize(&self) -> SerializedState<Self> { |
| 124 | + let mut dst = SerializedState::<Self>::default(); |
| 125 | + |
| 126 | + let (r_dst, tail) = dst.split_at_mut(16); |
| 127 | + let (s_dst, h_dst) = tail.split_at_mut(16); |
| 128 | + |
| 129 | + r_dst.copy_from_slice(&self.r.to_le_bytes()); |
| 130 | + write_u32s(&self.s, s_dst); |
| 131 | + write_u32s(&self.h, h_dst); |
| 132 | + |
| 133 | + dst |
| 134 | + } |
| 135 | + |
| 136 | + fn deserialize( |
| 137 | + serialized_state: &SerializedState<Self>, |
| 138 | + ) -> Result<Self, DeserializeStateError> { |
| 139 | + let (r_src, tail) = serialized_state.split_at(16); |
| 140 | + let (s_src, h_src) = tail.split_at(16); |
| 141 | + |
| 142 | + Ok(Self { |
| 143 | + r: u128::from_le_bytes(r_src.try_into().unwrap()), |
| 144 | + s: read_u32s(s_src), |
| 145 | + h: read_u32s(h_src), |
| 146 | + }) |
| 147 | + } |
| 148 | +} |
| 149 | + |
| 150 | +/// Compression function described in the section 6.3.2 |
| 151 | +#[inline(always)] |
| 152 | +pub fn belt_compress(x1: [u32; 4], x2: [u32; 4], x34: [u32; 8]) -> ([u32; 4], [u32; 8]) { |
| 153 | + let x3 = [x34[0], x34[1], x34[2], x34[3]]; |
| 154 | + let x4 = [x34[4], x34[5], x34[6], x34[7]]; |
| 155 | + |
| 156 | + // Step 2 |
| 157 | + let t1 = belt_block_raw(xor(x3, x4), &concat(x1, x2)); |
| 158 | + let s = xor(xor(t1, x3), x4); |
| 159 | + // Step 3 |
| 160 | + let t2 = belt_block_raw(x1, &concat(s, x4)); |
| 161 | + let y1 = xor(t2, x1); |
| 162 | + // Step 4 |
| 163 | + let t3 = belt_block_raw(x2, &concat(s.map(|v| !v), x3)); |
| 164 | + let y2 = xor(t3, x2); |
| 165 | + // Step 5 |
| 166 | + (s, concat(y1, y2)) |
| 167 | +} |
| 168 | + |
| 169 | +#[inline(always)] |
| 170 | +fn xor(a: [u32; 4], b: [u32; 4]) -> [u32; 4] { |
| 171 | + [a[0] ^ b[0], a[1] ^ b[1], a[2] ^ b[2], a[3] ^ b[3]] |
| 172 | +} |
| 173 | + |
| 174 | +#[inline(always)] |
| 175 | +fn concat(a: [u32; 4], b: [u32; 4]) -> [u32; 8] { |
| 176 | + [a[0], a[1], a[2], a[3], b[0], b[1], b[2], b[3]] |
| 177 | +} |
| 178 | + |
| 179 | +#[inline(always)] |
| 180 | +fn read_u32s<const N: usize>(src: &[u8]) -> [u32; N] { |
| 181 | + assert_eq!(src.len(), 4 * N); |
| 182 | + |
| 183 | + let mut dst = [0u32; N]; |
| 184 | + for (dst, src) in dst.iter_mut().zip(src.chunks_exact(4)) { |
| 185 | + *dst = u32::from_le_bytes(src.try_into().unwrap()); |
| 186 | + } |
| 187 | + dst |
| 188 | +} |
| 189 | + |
| 190 | +#[inline(always)] |
| 191 | +fn write_u32s(src: &[u32], dst: &mut [u8]) { |
| 192 | + assert_eq!(4 * src.len(), dst.len()); |
| 193 | + for (src, dst) in src.iter().zip(dst.chunks_exact_mut(4)) { |
| 194 | + dst.copy_from_slice(&src.to_le_bytes()); |
| 195 | + } |
| 196 | +} |
| 197 | + |
| 198 | +#[inline(always)] |
| 199 | +fn encode_r(r: u128) -> [u32; 4] { |
| 200 | + core::array::from_fn(|i| (r >> (32 * i)) as u32) |
| 201 | +} |
| 202 | + |
| 203 | +#[cfg(test)] |
| 204 | +mod tests { |
| 205 | + use super::{belt_compress, read_u32s}; |
| 206 | + use hex_literal::hex; |
| 207 | + |
| 208 | + /// Test vectors for the `belt-compress` functions from the |
| 209 | + /// specification (Table A.8). |
| 210 | + #[test] |
| 211 | + fn compress() { |
| 212 | + let x = &hex!( |
| 213 | + "B194BAC8 0A08F53B 366D008E 584A5DE4" |
| 214 | + "8504FA9D 1BB6C7AC 252E72C2 02FDCE0D" |
| 215 | + "5BE3D612 17B96181 FE6786AD 716B890B" |
| 216 | + "5CB0C0FF 33C356B8 35C405AE D8E07F99" |
| 217 | + ); |
| 218 | + let expected_s = &hex!("46FE7425 C9B181EB 41DFEE3E 72163D5A"); |
| 219 | + let expected_y = &hex!( |
| 220 | + "ED2F5481 D593F40D 87FCE37D 6BC1A2E1" |
| 221 | + "B7D1A2CC 975C82D3 C0497488 C90D99D8" |
| 222 | + ); |
| 223 | + let x1 = read_u32s(&x[..16]); |
| 224 | + let x2 = read_u32s(&x[16..32]); |
| 225 | + let x34 = read_u32s(&x[32..]); |
| 226 | + |
| 227 | + let (s, y) = belt_compress(x1, x2, x34); |
| 228 | + |
| 229 | + assert_eq!(s, read_u32s(expected_s)); |
| 230 | + assert_eq!(y, read_u32s(expected_y)); |
| 231 | + } |
| 232 | +} |
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