1 // SPDX-License-Identifier: GPL-2.0 OR MIT
3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
5 * This is based in part on Andrew Moon's poly1305-donna, which is in the
9 #include <linux/kernel.h>
10 #include <asm/unaligned.h>
11 #include <crypto/internal/poly1305.h>
13 void poly1305_core_setkey(struct poly1305_core_key *key, const u8 raw_key[16])
15 /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
16 key->key.r[0] = (get_unaligned_le32(&raw_key[0])) & 0x3ffffff;
17 key->key.r[1] = (get_unaligned_le32(&raw_key[3]) >> 2) & 0x3ffff03;
18 key->key.r[2] = (get_unaligned_le32(&raw_key[6]) >> 4) & 0x3ffc0ff;
19 key->key.r[3] = (get_unaligned_le32(&raw_key[9]) >> 6) & 0x3f03fff;
20 key->key.r[4] = (get_unaligned_le32(&raw_key[12]) >> 8) & 0x00fffff;
23 key->precomputed_s.r[0] = key->key.r[1] * 5;
24 key->precomputed_s.r[1] = key->key.r[2] * 5;
25 key->precomputed_s.r[2] = key->key.r[3] * 5;
26 key->precomputed_s.r[3] = key->key.r[4] * 5;
28 EXPORT_SYMBOL(poly1305_core_setkey);
30 void poly1305_core_blocks(struct poly1305_state *state,
31 const struct poly1305_core_key *key, const void *src,
32 unsigned int nblocks, u32 hibit)
34 const u8 *input = src;
35 u32 r0, r1, r2, r3, r4;
37 u32 h0, h1, h2, h3, h4;
38 u64 d0, d1, d2, d3, d4;
52 s1 = key->precomputed_s.r[0];
53 s2 = key->precomputed_s.r[1];
54 s3 = key->precomputed_s.r[2];
55 s4 = key->precomputed_s.r[3];
65 h0 += (get_unaligned_le32(&input[0])) & 0x3ffffff;
66 h1 += (get_unaligned_le32(&input[3]) >> 2) & 0x3ffffff;
67 h2 += (get_unaligned_le32(&input[6]) >> 4) & 0x3ffffff;
68 h3 += (get_unaligned_le32(&input[9]) >> 6) & 0x3ffffff;
69 h4 += (get_unaligned_le32(&input[12]) >> 8) | hibit;
72 d0 = ((u64)h0 * r0) + ((u64)h1 * s4) +
73 ((u64)h2 * s3) + ((u64)h3 * s2) +
75 d1 = ((u64)h0 * r1) + ((u64)h1 * r0) +
76 ((u64)h2 * s4) + ((u64)h3 * s3) +
78 d2 = ((u64)h0 * r2) + ((u64)h1 * r1) +
79 ((u64)h2 * r0) + ((u64)h3 * s4) +
81 d3 = ((u64)h0 * r3) + ((u64)h1 * r2) +
82 ((u64)h2 * r1) + ((u64)h3 * r0) +
84 d4 = ((u64)h0 * r4) + ((u64)h1 * r3) +
85 ((u64)h2 * r2) + ((u64)h3 * r1) +
88 /* (partial) h %= p */
90 h0 = (u32)d0 & 0x3ffffff;
93 h1 = (u32)d1 & 0x3ffffff;
96 h2 = (u32)d2 & 0x3ffffff;
99 h3 = (u32)d3 & 0x3ffffff;
102 h4 = (u32)d4 & 0x3ffffff;
108 input += POLY1305_BLOCK_SIZE;
117 EXPORT_SYMBOL(poly1305_core_blocks);
119 void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4],
123 u32 h0, h1, h2, h3, h4, c;
124 u32 g0, g1, g2, g3, g4;
164 g4 = h4 + c - (1UL << 26);
166 /* select h if h < p, or h + -p if h >= p */
167 mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1;
175 h0 = (h0 & mask) | g0;
176 h1 = (h1 & mask) | g1;
177 h2 = (h2 & mask) | g2;
178 h3 = (h3 & mask) | g3;
179 h4 = (h4 & mask) | g4;
181 /* h = h % (2^128) */
182 h0 = ((h0) | (h1 << 26)) & 0xffffffff;
183 h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff;
184 h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff;
185 h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff;
188 /* mac = (h + nonce) % (2^128) */
189 f = (u64)h0 + nonce[0];
191 f = (u64)h1 + nonce[1] + (f >> 32);
193 f = (u64)h2 + nonce[2] + (f >> 32);
195 f = (u64)h3 + nonce[3] + (f >> 32);
199 put_unaligned_le32(h0, &mac[0]);
200 put_unaligned_le32(h1, &mac[4]);
201 put_unaligned_le32(h2, &mac[8]);
202 put_unaligned_le32(h3, &mac[12]);
204 EXPORT_SYMBOL(poly1305_core_emit);