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 
secp256k1_sha256_initialize(secp256k1_sha256_t * hash)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. */
secp256k1_sha256_transform(uint32_t * s,const uint32_t * chunk)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 
secp256k1_sha256_write(secp256k1_sha256_t * hash,const unsigned char * data,size_t len)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 
secp256k1_sha256_finalize(secp256k1_sha256_t * hash,unsigned char * out32)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 
secp256k1_hmac_sha256_initialize(secp256k1_hmac_sha256_t * hash,const unsigned char * key,size_t keylen)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 
secp256k1_hmac_sha256_write(secp256k1_hmac_sha256_t * hash,const unsigned char * data,size_t size)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 
secp256k1_hmac_sha256_finalize(secp256k1_hmac_sha256_t * hash,unsigned char * out32)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 
secp256k1_rfc6979_hmac_sha256_initialize(secp256k1_rfc6979_hmac_sha256_t * rng,const unsigned char * key,size_t keylen)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 
secp256k1_rfc6979_hmac_sha256_generate(secp256k1_rfc6979_hmac_sha256_t * rng,unsigned char * out,size_t outlen)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 
secp256k1_rfc6979_hmac_sha256_finalize(secp256k1_rfc6979_hmac_sha256_t * rng)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
282