1// SHA-256. Adapted from https://github.com/kalven/sha-2, which was adapted
2// from LibTomCrypt. This code is Public Domain.
3
4#if !defined(CONF_OPENSSL)
5
6#include "hash_ctxt.h"
7
8#include <cstdint>
9#include <cstring>
10
11typedef uint32_t u32;
12typedef uint64_t u64;
13typedef SHA256_CTX sha256_state;
14
15static const u32 K[64] =
16 {
17 0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL, 0x3956c25bUL,
18 0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL, 0xd807aa98UL, 0x12835b01UL,
19 0x243185beUL, 0x550c7dc3UL, 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL,
20 0xc19bf174UL, 0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
21 0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL, 0x983e5152UL,
22 0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL, 0xc6e00bf3UL, 0xd5a79147UL,
23 0x06ca6351UL, 0x14292967UL, 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL,
24 0x53380d13UL, 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
25 0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL, 0xd192e819UL,
26 0xd6990624UL, 0xf40e3585UL, 0x106aa070UL, 0x19a4c116UL, 0x1e376c08UL,
27 0x2748774cUL, 0x34b0bcb5UL, 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL,
28 0x682e6ff3UL, 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
29 0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL};
30
31static u32 minimum(u32 x, u32 y)
32{
33 return x < y ? x : y;
34}
35
36static u32 load32(const unsigned char *y)
37{
38 return ((u32)y[0] << 24) | ((u32)y[1] << 16) | ((u32)y[2] << 8) | ((u32)y[3] << 0);
39}
40
41static void store64(u64 x, unsigned char *y)
42{
43 int i;
44 for(i = 0; i != 8; ++i)
45 y[i] = (x >> ((7 - i) * 8)) & 255;
46}
47
48static void store32(u32 x, unsigned char *y)
49{
50 int i;
51 for(i = 0; i != 4; ++i)
52 y[i] = (x >> ((3 - i) * 8)) & 255;
53}
54
55static u32 Ch(u32 x, u32 y, u32 z) { return z ^ (x & (y ^ z)); }
56static u32 Maj(u32 x, u32 y, u32 z) { return ((x | y) & z) | (x & y); }
57static u32 Rot(u32 x, u32 n) { return (x >> (n & 31)) | (x << (32 - (n & 31))); }
58static u32 Sh(u32 x, u32 n) { return x >> n; }
59static u32 Sigma0(u32 x) { return Rot(x, 2) ^ Rot(x, 13) ^ Rot(x, 22); }
60static u32 Sigma1(u32 x) { return Rot(x, 6) ^ Rot(x, 11) ^ Rot(x, 25); }
61static u32 Gamma0(u32 x) { return Rot(x, 7) ^ Rot(x, 18) ^ Sh(x, 3); }
62static u32 Gamma1(u32 x) { return Rot(x, 17) ^ Rot(x, 19) ^ Sh(x, 10); }
63
64static void sha_compress(sha256_state *md, const unsigned char *buf)
65{
66 u32 S[8], W[64], t;
67 int i;
68
69 // Copy state into S
70 for(i = 0; i < 8; i++)
71 S[i] = md->state[i];
72
73 // Copy the state into 512-bits into W[0..15]
74 for(i = 0; i < 16; i++)
75 W[i] = load32(buf + (4 * i));
76
77 // Fill W[16..63]
78 for(i = 16; i < 64; i++)
79 W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) + W[i - 16];
80
81// Compress
82#define RND(a, b, c, d, e, f, g, h, i) \
83 do \
84 { \
85 u32 t0 = (h) + Sigma1(e) + Ch(e, f, g) + K[i] + W[i]; \
86 u32 t1 = Sigma0(a) + Maj(a, b, c); \
87 (d) += t0; \
88 (h) = t0 + t1; \
89 } while(0)
90
91 for(i = 0; i < 64; ++i)
92 {
93 RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], i);
94 t = S[7];
95 S[7] = S[6];
96 S[6] = S[5];
97 S[5] = S[4];
98 S[4] = S[3];
99 S[3] = S[2];
100 S[2] = S[1];
101 S[1] = S[0];
102 S[0] = t;
103 }
104
105 // Feedback
106 for(i = 0; i < 8; i++)
107 md->state[i] = md->state[i] + S[i];
108}
109
110// Public interface
111
112static void sha_init(sha256_state *md)
113{
114 md->curlen = 0;
115 md->length = 0;
116 md->state[0] = 0x6A09E667UL;
117 md->state[1] = 0xBB67AE85UL;
118 md->state[2] = 0x3C6EF372UL;
119 md->state[3] = 0xA54FF53AUL;
120 md->state[4] = 0x510E527FUL;
121 md->state[5] = 0x9B05688CUL;
122 md->state[6] = 0x1F83D9ABUL;
123 md->state[7] = 0x5BE0CD19UL;
124}
125
126static void sha_process(sha256_state *md, const void *src, u32 inlen)
127{
128 const u32 block_size = 64;
129 const unsigned char *in = (const unsigned char *)src;
130
131 while(inlen > 0)
132 {
133 if(md->curlen == 0 && inlen >= block_size)
134 {
135 sha_compress(md, in);
136 md->length += block_size * 8;
137 in += block_size;
138 inlen -= block_size;
139 }
140 else
141 {
142 u32 n = minimum(inlen, (block_size - md->curlen));
143 memcpy(md->buf + md->curlen, in, n);
144 md->curlen += n;
145 in += n;
146 inlen -= n;
147
148 if(md->curlen == block_size)
149 {
150 sha_compress(md, md->buf);
151 md->length += 8 * block_size;
152 md->curlen = 0;
153 }
154 }
155 }
156}
157
158static void sha_done(sha256_state *md, void *out)
159{
160 int i;
161
162 // Increase the length of the message
163 md->length += md->curlen * 8;
164
165 // Append the '1' bit
166 md->buf[md->curlen++] = (unsigned char)0x80;
167
168 // If the length is currently above 56 bytes we append zeros then compress.
169 // Then we can fall back to padding zeros and length encoding like normal.
170 if(md->curlen > 56)
171 {
172 while(md->curlen < 64)
173 md->buf[md->curlen++] = 0;
174 sha_compress(md, md->buf);
175 md->curlen = 0;
176 }
177
178 // Pad up to 56 bytes of zeroes
179 while(md->curlen < 56)
180 md->buf[md->curlen++] = 0;
181
182 // Store length
183 store64(md->length, md->buf + 56);
184 sha_compress(md, md->buf);
185
186 // Copy output
187 for(i = 0; i < 8; i++)
188 store32(md->state[i], (unsigned char *)out + (4 * i));
189}
190
191void sha256_init(SHA256_CTX *ctxt)
192{
193 sha_init(ctxt);
194}
195
196void sha256_update(SHA256_CTX *ctxt, const void *data, size_t data_len)
197{
198 sha_process(ctxt, data, data_len);
199}
200
201SHA256_DIGEST sha256_finish(SHA256_CTX *ctxt)
202{
203 SHA256_DIGEST result;
204 sha_done(ctxt, result.data);
205 return result;
206}
207
208#endif
209