src/hash_impl.h

   1 /**********************************************************************
   2  * Copyright (c) 2014 Pieter Wuille                                   *
   3  * Distributed under the MIT software license, see the accompanying   *
   4  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
   5  **********************************************************************/
   6
   7 #ifndef SECP256K1_HASH_IMPL_H
   8 #define SECP256K1_HASH_IMPL_H
   9
  10 #include "hash.h"
  11
  12 #include <stdlib.h>
  13 #include <stdint.h>
  14 #include <string.h>
  15
  16 #define Ch(x,y,z) ((z) ^ ((x) & ((y) ^ (z))))
  17 #define Maj(x,y,z) (((x) & (y)) | ((z) & ((x) | (y))))
  18 #define Sigma0(x) (((x) >> 2 | (x) << 30) ^ ((x) >> 13 | (x) << 19) ^ ((x) >> 22 | (x) << 10))
  19 #define Sigma1(x) (((x) >> 6 | (x) << 26) ^ ((x) >> 11 | (x) << 21) ^ ((x) >> 25 | (x) << 7))
  20 #define sigma0(x) (((x) >> 7 | (x) << 25) ^ ((x) >> 18 | (x) << 14) ^ ((x) >> 3))
  21 #define sigma1(x) (((x) >> 17 | (x) << 15) ^ ((x) >> 19 | (x) << 13) ^ ((x) >> 10))
  22
  23 #define Round(a,b,c,d,e,f,g,h,k,w) do { \
  24     uint32_t t1 = (h) + Sigma1(e) + Ch((e), (f), (g)) + (k) + (w); \
  25     uint32_t t2 = Sigma0(a) + Maj((a), (b), (c)); \
  26     (d) += t1; \
  27     (h) = t1 + t2; \
  28 } while(0)
  29
  30 #ifdef WORDS_BIGENDIAN
  31 #define BE32(x) (x)
  32 #else
  33 #define BE32(p) ((((p) & 0xFF) << 24) | (((p) & 0xFF00) << 8) | (((p) & 0xFF0000) >> 8) | (((p) & 0xFF000000) >> 24))
  34 #endif
  35
  36 static void secp256k1_sha256_initialize(secp256k1_sha256_t *hash) {
  37     hash->s[0] = 0x6a09e667ul;
  38     hash->s[1] = 0xbb67ae85ul;
  39     hash->s[2] = 0x3c6ef372ul;
  40     hash->s[3] = 0xa54ff53aul;
  41     hash->s[4] = 0x510e527ful;
  42     hash->s[5] = 0x9b05688cul;
  43     hash->s[6] = 0x1f83d9abul;
  44     hash->s[7] = 0x5be0cd19ul;
  45     hash->bytes = 0;
  46 }
  47
  48 /** Perform one SHA-256 transformation, processing 16 big endian 32-bit words. */
  49 static void secp256k1_sha256_transform(uint32_t* s, const uint32_t* chunk) {
  50     uint32_t a = s[0], b = s[1], c = s[2], d = s[3], e = s[4], f = s[5], g = s[6], h = s[7];
  51     uint32_t w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15;
  52
  53     Round(a, b, c, d, e, f, g, h, 0x428a2f98, w0 = BE32(chunk[0]));
  54     Round(h, a, b, c, d, e, f, g, 0x71374491, w1 = BE32(chunk[1]));
  55     Round(g, h, a, b, c, d, e, f, 0xb5c0fbcf, w2 = BE32(chunk[2]));
  56     Round(f, g, h, a, b, c, d, e, 0xe9b5dba5, w3 = BE32(chunk[3]));
  57     Round(e, f, g, h, a, b, c, d, 0x3956c25b, w4 = BE32(chunk[4]));
  58     Round(d, e, f, g, h, a, b, c, 0x59f111f1, w5 = BE32(chunk[5]));
  59     Round(c, d, e, f, g, h, a, b, 0x923f82a4, w6 = BE32(chunk[6]));
  60     Round(b, c, d, e, f, g, h, a, 0xab1c5ed5, w7 = BE32(chunk[7]));
  61     Round(a, b, c, d, e, f, g, h, 0xd807aa98, w8 = BE32(chunk[8]));
  62     Round(h, a, b, c, d, e, f, g, 0x12835b01, w9 = BE32(chunk[9]));
  63     Round(g, h, a, b, c, d, e, f, 0x243185be, w10 = BE32(chunk[10]));
  64     Round(f, g, h, a, b, c, d, e, 0x550c7dc3, w11 = BE32(chunk[11]));
  65     Round(e, f, g, h, a, b, c, d, 0x72be5d74, w12 = BE32(chunk[12]));
  66     Round(d, e, f, g, h, a, b, c, 0x80deb1fe, w13 = BE32(chunk[13]));
  67     Round(c, d, e, f, g, h, a, b, 0x9bdc06a7, w14 = BE32(chunk[14]));
  68     Round(b, c, d, e, f, g, h, a, 0xc19bf174, w15 = BE32(chunk[15]));
  69
  70     Round(a, b, c, d, e, f, g, h, 0xe49b69c1, w0 += sigma1(w14) + w9 + sigma0(w1));
  71     Round(h, a, b, c, d, e, f, g, 0xefbe4786, w1 += sigma1(w15) + w10 + sigma0(w2));
  72     Round(g, h, a, b, c, d, e, f, 0x0fc19dc6, w2 += sigma1(w0) + w11 + sigma0(w3));
  73     Round(f, g, h, a, b, c, d, e, 0x240ca1cc, w3 += sigma1(w1) + w12 + sigma0(w4));
  74     Round(e, f, g, h, a, b, c, d, 0x2de92c6f, w4 += sigma1(w2) + w13 + sigma0(w5));
  75     Round(d, e, f, g, h, a, b, c, 0x4a7484aa, w5 += sigma1(w3) + w14 + sigma0(w6));
  76     Round(c, d, e, f, g, h, a, b, 0x5cb0a9dc, w6 += sigma1(w4) + w15 + sigma0(w7));
  77     Round(b, c, d, e, f, g, h, a, 0x76f988da, w7 += sigma1(w5) + w0 + sigma0(w8));
  78     Round(a, b, c, d, e, f, g, h, 0x983e5152, w8 += sigma1(w6) + w1 + sigma0(w9));
  79     Round(h, a, b, c, d, e, f, g, 0xa831c66d, w9 += sigma1(w7) + w2 + sigma0(w10));
  80     Round(g, h, a, b, c, d, e, f, 0xb00327c8, w10 += sigma1(w8) + w3 + sigma0(w11));
  81     Round(f, g, h, a, b, c, d, e, 0xbf597fc7, w11 += sigma1(w9) + w4 + sigma0(w12));
  82     Round(e, f, g, h, a, b, c, d, 0xc6e00bf3, w12 += sigma1(w10) + w5 + sigma0(w13));
  83     Round(d, e, f, g, h, a, b, c, 0xd5a79147, w13 += sigma1(w11) + w6 + sigma0(w14));
  84     Round(c, d, e, f, g, h, a, b, 0x06ca6351, w14 += sigma1(w12) + w7 + sigma0(w15));
  85     Round(b, c, d, e, f, g, h, a, 0x14292967, w15 += sigma1(w13) + w8 + sigma0(w0));
  86
  87     Round(a, b, c, d, e, f, g, h, 0x27b70a85, w0 += sigma1(w14) + w9 + sigma0(w1));
  88     Round(h, a, b, c, d, e, f, g, 0x2e1b2138, w1 += sigma1(w15) + w10 + sigma0(w2));
  89     Round(g, h, a, b, c, d, e, f, 0x4d2c6dfc, w2 += sigma1(w0) + w11 + sigma0(w3));
  90     Round(f, g, h, a, b, c, d, e, 0x53380d13, w3 += sigma1(w1) + w12 + sigma0(w4));
  91     Round(e, f, g, h, a, b, c, d, 0x650a7354, w4 += sigma1(w2) + w13 + sigma0(w5));
  92     Round(d, e, f, g, h, a, b, c, 0x766a0abb, w5 += sigma1(w3) + w14 + sigma0(w6));
  93     Round(c, d, e, f, g, h, a, b, 0x81c2c92e, w6 += sigma1(w4) + w15 + sigma0(w7));
  94     Round(b, c, d, e, f, g, h, a, 0x92722c85, w7 += sigma1(w5) + w0 + sigma0(w8));
  95     Round(a, b, c, d, e, f, g, h, 0xa2bfe8a1, w8 += sigma1(w6) + w1 + sigma0(w9));
  96     Round(h, a, b, c, d, e, f, g, 0xa81a664b, w9 += sigma1(w7) + w2 + sigma0(w10));
  97     Round(g, h, a, b, c, d, e, f, 0xc24b8b70, w10 += sigma1(w8) + w3 + sigma0(w11));
  98     Round(f, g, h, a, b, c, d, e, 0xc76c51a3, w11 += sigma1(w9) + w4 + sigma0(w12));
  99     Round(e, f, g, h, a, b, c, d, 0xd192e819, w12 += sigma1(w10) + w5 + sigma0(w13));
 100     Round(d, e, f, g, h, a, b, c, 0xd6990624, w13 += sigma1(w11) + w6 + sigma0(w14));
 101     Round(c, d, e, f, g, h, a, b, 0xf40e3585, w14 += sigma1(w12) + w7 + sigma0(w15));
 102     Round(b, c, d, e, f, g, h, a, 0x106aa070, w15 += sigma1(w13) + w8 + sigma0(w0));
 103
 104     Round(a, b, c, d, e, f, g, h, 0x19a4c116, w0 += sigma1(w14) + w9 + sigma0(w1));
 105     Round(h, a, b, c, d, e, f, g, 0x1e376c08, w1 += sigma1(w15) + w10 + sigma0(w2));
 106     Round(g, h, a, b, c, d, e, f, 0x2748774c, w2 += sigma1(w0) + w11 + sigma0(w3));
 107     Round(f, g, h, a, b, c, d, e, 0x34b0bcb5, w3 += sigma1(w1) + w12 + sigma0(w4));
 108     Round(e, f, g, h, a, b, c, d, 0x391c0cb3, w4 += sigma1(w2) + w13 + sigma0(w5));
 109     Round(d, e, f, g, h, a, b, c, 0x4ed8aa4a, w5 += sigma1(w3) + w14 + sigma0(w6));
 110     Round(c, d, e, f, g, h, a, b, 0x5b9cca4f, w6 += sigma1(w4) + w15 + sigma0(w7));
 111     Round(b, c, d, e, f, g, h, a, 0x682e6ff3, w7 += sigma1(w5) + w0 + sigma0(w8));
 112     Round(a, b, c, d, e, f, g, h, 0x748f82ee, w8 += sigma1(w6) + w1 + sigma0(w9));
 113     Round(h, a, b, c, d, e, f, g, 0x78a5636f, w9 += sigma1(w7) + w2 + sigma0(w10));
 114     Round(g, h, a, b, c, d, e, f, 0x84c87814, w10 += sigma1(w8) + w3 + sigma0(w11));
 115     Round(f, g, h, a, b, c, d, e, 0x8cc70208, w11 += sigma1(w9) + w4 + sigma0(w12));
 116     Round(e, f, g, h, a, b, c, d, 0x90befffa, w12 += sigma1(w10) + w5 + sigma0(w13));
 117     Round(d, e, f, g, h, a, b, c, 0xa4506ceb, w13 += sigma1(w11) + w6 + sigma0(w14));
 118     Round(c, d, e, f, g, h, a, b, 0xbef9a3f7, w14 + sigma1(w12) + w7 + sigma0(w15));
 119     Round(b, c, d, e, f, g, h, a, 0xc67178f2, w15 + sigma1(w13) + w8 + sigma0(w0));
 120
 121     s[0] += a;
 122     s[1] += b;
 123     s[2] += c;
 124     s[3] += d;
 125     s[4] += e;
 126     s[5] += f;
 127     s[6] += g;
 128     s[7] += h;
 129 }
 130
 131 static void secp256k1_sha256_write(secp256k1_sha256_t *hash, const unsigned char *data, size_t len) {
 132     size_t bufsize = hash->bytes & 0x3F;
 133     hash->bytes += len;
 134     while (bufsize + len >= 64) {
 135         /* Fill the buffer, and process it. */
 136         memcpy(((unsigned char*)hash->buf) + bufsize, data, 64 - bufsize);
 137         data += 64 - bufsize;
 138         len -= 64 - bufsize;
 139         secp256k1_sha256_transform(hash->s, hash->buf);
 140         bufsize = 0;
 141     }
 142     if (len) {
 143         /* Fill the buffer with what remains. */
 144         memcpy(((unsigned char*)hash->buf) + bufsize, data, len);
 145     }
 146 }
 147
 148 static void secp256k1_sha256_finalize(secp256k1_sha256_t *hash, unsigned char *out32) {
 149     static const unsigned char pad[64] = {0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 150     uint32_t sizedesc[2];
 151     uint32_t out[8];
 152     int i = 0;
 153     sizedesc[0] = BE32(hash->bytes >> 29);
 154     sizedesc[1] = BE32(hash->bytes << 3);
 155     secp256k1_sha256_write(hash, pad, 1 + ((119 - (hash->bytes % 64)) % 64));
 156     secp256k1_sha256_write(hash, (const unsigned char*)sizedesc, 8);
 157     for (i = 0; i < 8; i++) {
 158         out[i] = BE32(hash->s[i]);
 159         hash->s[i] = 0;
 160     }
 161     memcpy(out32, (const unsigned char*)out, 32);
 162 }
 163
 164 static void secp256k1_hmac_sha256_initialize(secp256k1_hmac_sha256_t *hash, const unsigned char *key, size_t keylen) {
 165     int n;
 166     unsigned char rkey[64];
 167     if (keylen <= 64) {
 168         memcpy(rkey, key, keylen);
 169         memset(rkey + keylen, 0, 64 - keylen);
 170     } else {
 171         secp256k1_sha256_t sha256;
 172         secp256k1_sha256_initialize(&sha256);
 173         secp256k1_sha256_write(&sha256, key, keylen);
 174         secp256k1_sha256_finalize(&sha256, rkey);
 175         memset(rkey + 32, 0, 32);
 176     }
 177
 178     secp256k1_sha256_initialize(&hash->outer);
 179     for (n = 0; n < 64; n++) {
 180         rkey[n] ^= 0x5c;
 181     }
 182     secp256k1_sha256_write(&hash->outer, rkey, 64);
 183
 184     secp256k1_sha256_initialize(&hash->inner);
 185     for (n = 0; n < 64; n++) {
 186         rkey[n] ^= 0x5c ^ 0x36;
 187     }
 188     secp256k1_sha256_write(&hash->inner, rkey, 64);
 189     memset(rkey, 0, 64);
 190 }
 191
 192 static void secp256k1_hmac_sha256_write(secp256k1_hmac_sha256_t *hash, const unsigned char *data, size_t size) {
 193     secp256k1_sha256_write(&hash->inner, data, size);
 194 }
 195
 196 static void secp256k1_hmac_sha256_finalize(secp256k1_hmac_sha256_t *hash, unsigned char *out32) {
 197     unsigned char temp[32];
 198     secp256k1_sha256_finalize(&hash->inner, temp);
 199     secp256k1_sha256_write(&hash->outer, temp, 32);
 200     memset(temp, 0, 32);
 201     secp256k1_sha256_finalize(&hash->outer, out32);
 202 }
 203
 204
 205 static void secp256k1_rfc6979_hmac_sha256_initialize(secp256k1_rfc6979_hmac_sha256_t *rng, const unsigned char *key, size_t keylen) {
 206     secp256k1_hmac_sha256_t hmac;
 207     static const unsigned char zero[1] = {0x00};
 208     static const unsigned char one[1] = {0x01};
 209
 210     memset(rng->v, 0x01, 32); /* RFC6979 3.2.b. */
 211     memset(rng->k, 0x00, 32); /* RFC6979 3.2.c. */
 212
 213     /* RFC6979 3.2.d. */
 214     secp256k1_hmac_sha256_initialize(&hmac, rng->k, 32);
 215     secp256k1_hmac_sha256_write(&hmac, rng->v, 32);
 216     secp256k1_hmac_sha256_write(&hmac, zero, 1);
 217     secp256k1_hmac_sha256_write(&hmac, key, keylen);
 218     secp256k1_hmac_sha256_finalize(&hmac, rng->k);
 219     secp256k1_hmac_sha256_initialize(&hmac, rng->k, 32);
 220     secp256k1_hmac_sha256_write(&hmac, rng->v, 32);
 221     secp256k1_hmac_sha256_finalize(&hmac, rng->v);
 222
 223     /* RFC6979 3.2.f. */
 224     secp256k1_hmac_sha256_initialize(&hmac, rng->k, 32);
 225     secp256k1_hmac_sha256_write(&hmac, rng->v, 32);
 226     secp256k1_hmac_sha256_write(&hmac, one, 1);
 227     secp256k1_hmac_sha256_write(&hmac, key, keylen);
 228     secp256k1_hmac_sha256_finalize(&hmac, rng->k);
 229     secp256k1_hmac_sha256_initialize(&hmac, rng->k, 32);
 230     secp256k1_hmac_sha256_write(&hmac, rng->v, 32);
 231     secp256k1_hmac_sha256_finalize(&hmac, rng->v);
 232     rng->retry = 0;
 233 }
 234
 235 static void secp256k1_rfc6979_hmac_sha256_generate(secp256k1_rfc6979_hmac_sha256_t *rng, unsigned char *out, size_t outlen) {
 236     /* RFC6979 3.2.h. */
 237     static const unsigned char zero[1] = {0x00};
 238     if (rng->retry) {
 239         secp256k1_hmac_sha256_t hmac;
 240         secp256k1_hmac_sha256_initialize(&hmac, rng->k, 32);
 241         secp256k1_hmac_sha256_write(&hmac, rng->v, 32);
 242         secp256k1_hmac_sha256_write(&hmac, zero, 1);
 243         secp256k1_hmac_sha256_finalize(&hmac, rng->k);
 244         secp256k1_hmac_sha256_initialize(&hmac, rng->k, 32);
 245         secp256k1_hmac_sha256_write(&hmac, rng->v, 32);
 246         secp256k1_hmac_sha256_finalize(&hmac, rng->v);
 247     }
 248
 249     while (outlen > 0) {
 250         secp256k1_hmac_sha256_t hmac;
 251         int now = outlen;
 252         secp256k1_hmac_sha256_initialize(&hmac, rng->k, 32);
 253         secp256k1_hmac_sha256_write(&hmac, rng->v, 32);
 254         secp256k1_hmac_sha256_finalize(&hmac, rng->v);
 255         if (now > 32) {
 256             now = 32;
 257         }
 258         memcpy(out, rng->v, now);
 259         out += now;
 260         outlen -= now;
 261     }
 262
 263     rng->retry = 1;
 264 }
 265
 266 static void secp256k1_rfc6979_hmac_sha256_finalize(secp256k1_rfc6979_hmac_sha256_t *rng) {
 267     memset(rng->k, 0, 32);
 268     memset(rng->v, 0, 32);
 269     rng->retry = 0;
 270 }
 271
 272 #undef BE32
 273 #undef Round
 274 #undef sigma1
 275 #undef sigma0
 276 #undef Sigma1
 277 #undef Sigma0
 278 #undef Maj
 279 #undef Ch
 280
 281 #endif /* SECP256K1_HASH_IMPL_H */