Bitcoin Core  0.19.99
P2P Digital Currency
poly1305.cpp
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1 // Copyright (c) 2019 The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 
5 // Based on the public domain implementation by Andrew Moon
6 // poly1305-donna-unrolled.c from https://github.com/floodyberry/poly1305-donna
7 
8 #include <crypto/common.h>
9 #include <crypto/poly1305.h>
10 
11 #include <string.h>
12 
13 #define mul32x32_64(a,b) ((uint64_t)(a) * (b))
14 
15 void poly1305_auth(unsigned char out[POLY1305_TAGLEN], const unsigned char *m, size_t inlen, const unsigned char key[POLY1305_KEYLEN]) {
16  uint32_t t0,t1,t2,t3;
17  uint32_t h0,h1,h2,h3,h4;
18  uint32_t r0,r1,r2,r3,r4;
19  uint32_t s1,s2,s3,s4;
20  uint32_t b, nb;
21  size_t j;
22  uint64_t t[5];
23  uint64_t f0,f1,f2,f3;
24  uint64_t g0,g1,g2,g3,g4;
25  uint64_t c;
26  unsigned char mp[16];
27 
28  /* clamp key */
29  t0 = ReadLE32(key+0);
30  t1 = ReadLE32(key+4);
31  t2 = ReadLE32(key+8);
32  t3 = ReadLE32(key+12);
33 
34  /* precompute multipliers */
35  r0 = t0 & 0x3ffffff; t0 >>= 26; t0 |= t1 << 6;
36  r1 = t0 & 0x3ffff03; t1 >>= 20; t1 |= t2 << 12;
37  r2 = t1 & 0x3ffc0ff; t2 >>= 14; t2 |= t3 << 18;
38  r3 = t2 & 0x3f03fff; t3 >>= 8;
39  r4 = t3 & 0x00fffff;
40 
41  s1 = r1 * 5;
42  s2 = r2 * 5;
43  s3 = r3 * 5;
44  s4 = r4 * 5;
45 
46  /* init state */
47  h0 = 0;
48  h1 = 0;
49  h2 = 0;
50  h3 = 0;
51  h4 = 0;
52 
53  /* full blocks */
54  if (inlen < 16) goto poly1305_donna_atmost15bytes;
55 poly1305_donna_16bytes:
56  m += 16;
57  inlen -= 16;
58 
59  t0 = ReadLE32(m-16);
60  t1 = ReadLE32(m-12);
61  t2 = ReadLE32(m-8);
62  t3 = ReadLE32(m-4);
63 
64  h0 += t0 & 0x3ffffff;
65  h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff;
66  h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff;
67  h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff;
68  h4 += (t3 >> 8) | (1 << 24);
69 
70 
71 poly1305_donna_mul:
72  t[0] = mul32x32_64(h0,r0) + mul32x32_64(h1,s4) + mul32x32_64(h2,s3) + mul32x32_64(h3,s2) + mul32x32_64(h4,s1);
73  t[1] = mul32x32_64(h0,r1) + mul32x32_64(h1,r0) + mul32x32_64(h2,s4) + mul32x32_64(h3,s3) + mul32x32_64(h4,s2);
74  t[2] = mul32x32_64(h0,r2) + mul32x32_64(h1,r1) + mul32x32_64(h2,r0) + mul32x32_64(h3,s4) + mul32x32_64(h4,s3);
75  t[3] = mul32x32_64(h0,r3) + mul32x32_64(h1,r2) + mul32x32_64(h2,r1) + mul32x32_64(h3,r0) + mul32x32_64(h4,s4);
76  t[4] = mul32x32_64(h0,r4) + mul32x32_64(h1,r3) + mul32x32_64(h2,r2) + mul32x32_64(h3,r1) + mul32x32_64(h4,r0);
77 
78  h0 = (uint32_t)t[0] & 0x3ffffff; c = (t[0] >> 26);
79  t[1] += c; h1 = (uint32_t)t[1] & 0x3ffffff; b = (uint32_t)(t[1] >> 26);
80  t[2] += b; h2 = (uint32_t)t[2] & 0x3ffffff; b = (uint32_t)(t[2] >> 26);
81  t[3] += b; h3 = (uint32_t)t[3] & 0x3ffffff; b = (uint32_t)(t[3] >> 26);
82  t[4] += b; h4 = (uint32_t)t[4] & 0x3ffffff; b = (uint32_t)(t[4] >> 26);
83  h0 += b * 5;
84 
85  if (inlen >= 16) goto poly1305_donna_16bytes;
86 
87  /* final bytes */
88 poly1305_donna_atmost15bytes:
89  if (!inlen) goto poly1305_donna_finish;
90 
91  for (j = 0; j < inlen; j++) mp[j] = m[j];
92  mp[j++] = 1;
93  for (; j < 16; j++) mp[j] = 0;
94  inlen = 0;
95 
96  t0 = ReadLE32(mp+0);
97  t1 = ReadLE32(mp+4);
98  t2 = ReadLE32(mp+8);
99  t3 = ReadLE32(mp+12);
100 
101  h0 += t0 & 0x3ffffff;
102  h1 += ((((uint64_t)t1 << 32) | t0) >> 26) & 0x3ffffff;
103  h2 += ((((uint64_t)t2 << 32) | t1) >> 20) & 0x3ffffff;
104  h3 += ((((uint64_t)t3 << 32) | t2) >> 14) & 0x3ffffff;
105  h4 += (t3 >> 8);
106 
107  goto poly1305_donna_mul;
108 
109 poly1305_donna_finish:
110  b = h0 >> 26; h0 = h0 & 0x3ffffff;
111  h1 += b; b = h1 >> 26; h1 = h1 & 0x3ffffff;
112  h2 += b; b = h2 >> 26; h2 = h2 & 0x3ffffff;
113  h3 += b; b = h3 >> 26; h3 = h3 & 0x3ffffff;
114  h4 += b; b = h4 >> 26; h4 = h4 & 0x3ffffff;
115  h0 += b * 5; b = h0 >> 26; h0 = h0 & 0x3ffffff;
116  h1 += b;
117 
118  g0 = h0 + 5; b = g0 >> 26; g0 &= 0x3ffffff;
119  g1 = h1 + b; b = g1 >> 26; g1 &= 0x3ffffff;
120  g2 = h2 + b; b = g2 >> 26; g2 &= 0x3ffffff;
121  g3 = h3 + b; b = g3 >> 26; g3 &= 0x3ffffff;
122  g4 = h4 + b - (1 << 26);
123 
124  b = (g4 >> 31) - 1;
125  nb = ~b;
126  h0 = (h0 & nb) | (g0 & b);
127  h1 = (h1 & nb) | (g1 & b);
128  h2 = (h2 & nb) | (g2 & b);
129  h3 = (h3 & nb) | (g3 & b);
130  h4 = (h4 & nb) | (g4 & b);
131 
132  f0 = ((h0 ) | (h1 << 26)) + (uint64_t)ReadLE32(&key[16]);
133  f1 = ((h1 >> 6) | (h2 << 20)) + (uint64_t)ReadLE32(&key[20]);
134  f2 = ((h2 >> 12) | (h3 << 14)) + (uint64_t)ReadLE32(&key[24]);
135  f3 = ((h3 >> 18) | (h4 << 8)) + (uint64_t)ReadLE32(&key[28]);
136 
137  WriteLE32(&out[ 0], f0); f1 += (f0 >> 32);
138  WriteLE32(&out[ 4], f1); f2 += (f1 >> 32);
139  WriteLE32(&out[ 8], f2); f3 += (f2 >> 32);
140  WriteLE32(&out[12], f3);
141 }
#define POLY1305_TAGLEN
Definition: poly1305.h:12
static void WriteLE32(unsigned char *ptr, uint32_t x)
Definition: common.h:44
void poly1305_auth(unsigned char out[POLY1305_TAGLEN], const unsigned char *m, size_t inlen, const unsigned char key[POLY1305_KEYLEN])
Definition: poly1305.cpp:15
static uint32_t ReadLE32(const unsigned char *ptr)
Definition: common.h:24
#define POLY1305_KEYLEN
Definition: poly1305.h:11
#define mul32x32_64(a, b)
Definition: poly1305.cpp:13