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| 1 | +// SPDX-License-Identifier: Apache-2.0 |
| 2 | +// This file is part of Frontier. |
| 3 | +// |
| 4 | +// Copyright (c) 2020-2022 Parity Technologies (UK) Ltd. |
| 5 | +// |
| 6 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 7 | +// you may not use this file except in compliance with the License. |
| 8 | +// You may obtain a copy of the License at |
| 9 | +// |
| 10 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | +// |
| 12 | +// Unless required by applicable law or agreed to in writing, software |
| 13 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | +// See the License for the specific language governing permissions and |
| 16 | +// limitations under the License. |
| 17 | + |
| 18 | +/// The precomputed values for BLAKE2b [from the |
| 19 | +/// spec](https://tools.ietf.org/html/rfc7693#section-2.7) There are 10 16-byte arrays - one for |
| 20 | +/// each round the entries are calculated from the sigma constants. |
| 21 | +const SIGMA: [[usize; 16]; 10] = [ |
| 22 | + [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], |
| 23 | + [14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3], |
| 24 | + [11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4], |
| 25 | + [7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8], |
| 26 | + [9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13], |
| 27 | + [2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9], |
| 28 | + [12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11], |
| 29 | + [13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10], |
| 30 | + [6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5], |
| 31 | + [10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0], |
| 32 | +]; |
| 33 | + |
| 34 | +/// IV is the initialization vector for BLAKE2b. See https://tools.ietf.org/html/rfc7693#section-2.6 |
| 35 | +/// for details. |
| 36 | +const IV: [u64; 8] = [ |
| 37 | + 0x6a09e667f3bcc908, |
| 38 | + 0xbb67ae8584caa73b, |
| 39 | + 0x3c6ef372fe94f82b, |
| 40 | + 0xa54ff53a5f1d36f1, |
| 41 | + 0x510e527fade682d1, |
| 42 | + 0x9b05688c2b3e6c1f, |
| 43 | + 0x1f83d9abfb41bd6b, |
| 44 | + 0x5be0cd19137e2179, |
| 45 | +]; |
| 46 | + |
| 47 | +#[inline(always)] |
| 48 | +/// The G mixing function. See https://tools.ietf.org/html/rfc7693#section-3.1 |
| 49 | +fn g(v: &mut [u64], a: usize, b: usize, c: usize, d: usize, x: u64, y: u64) { |
| 50 | + v[a] = v[a].wrapping_add(v[b]).wrapping_add(x); |
| 51 | + v[d] = (v[d] ^ v[a]).rotate_right(32); |
| 52 | + v[c] = v[c].wrapping_add(v[d]); |
| 53 | + v[b] = (v[b] ^ v[c]).rotate_right(24); |
| 54 | + v[a] = v[a].wrapping_add(v[b]).wrapping_add(y); |
| 55 | + v[d] = (v[d] ^ v[a]).rotate_right(16); |
| 56 | + v[c] = v[c].wrapping_add(v[d]); |
| 57 | + v[b] = (v[b] ^ v[c]).rotate_right(63); |
| 58 | +} |
| 59 | + |
| 60 | +/// The Blake2 compression function F. See https://tools.ietf.org/html/rfc7693#section-3.2 |
| 61 | +/// Takes as an argument the state vector `h`, message block vector `m`, offset counter `t`, final |
| 62 | +/// block indicator flag `f`, and number of rounds `rounds`. The state vector provided as the first |
| 63 | +/// parameter is modified by the function. |
| 64 | +pub fn compress(h: &mut [u64; 8], m: [u64; 16], t: [u64; 2], f: bool, rounds: usize) { |
| 65 | + let mut v = [0u64; 16]; |
| 66 | + v[..h.len()].copy_from_slice(h); // First half from state. |
| 67 | + v[h.len()..].copy_from_slice(&IV); // Second half from IV. |
| 68 | + |
| 69 | + v[12] ^= t[0]; |
| 70 | + v[13] ^= t[1]; |
| 71 | + |
| 72 | + if f { |
| 73 | + v[14] = !v[14] // Invert all bits if the last-block-flag is set. |
| 74 | + } |
| 75 | + for i in 0..rounds { |
| 76 | + // Message word selection permutation for this round. |
| 77 | + let s = &SIGMA[i % 10]; |
| 78 | + g(&mut v, 0, 4, 8, 12, m[s[0]], m[s[1]]); |
| 79 | + g(&mut v, 1, 5, 9, 13, m[s[2]], m[s[3]]); |
| 80 | + g(&mut v, 2, 6, 10, 14, m[s[4]], m[s[5]]); |
| 81 | + g(&mut v, 3, 7, 11, 15, m[s[6]], m[s[7]]); |
| 82 | + |
| 83 | + g(&mut v, 0, 5, 10, 15, m[s[8]], m[s[9]]); |
| 84 | + g(&mut v, 1, 6, 11, 12, m[s[10]], m[s[11]]); |
| 85 | + g(&mut v, 2, 7, 8, 13, m[s[12]], m[s[13]]); |
| 86 | + g(&mut v, 3, 4, 9, 14, m[s[14]], m[s[15]]); |
| 87 | + } |
| 88 | + |
| 89 | + for i in 0..8 { |
| 90 | + h[i] ^= v[i] ^ v[i + 8]; |
| 91 | + } |
| 92 | +} |
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