3 /* Process LEN bytes of BUFFER, accumulating context into CTX.
4 It is assumed that LEN % 64 == 0. */
6 sha256_process_block (const void *buffer, size_t len, struct sha256_ctx *ctx)
8 const uint32_t *words = buffer;
9 size_t nwords = len / sizeof (uint32_t);
10 uint32_t a = ctx->H[0];
11 uint32_t b = ctx->H[1];
12 uint32_t c = ctx->H[2];
13 uint32_t d = ctx->H[3];
14 uint32_t e = ctx->H[4];
15 uint32_t f = ctx->H[5];
16 uint32_t g = ctx->H[6];
17 uint32_t h = ctx->H[7];
19 /* First increment the byte count. FIPS 180-2 specifies the possible
20 length of the file up to 2^64 bits. Here we only compute the
24 /* Process all bytes in the buffer with 64 bytes in each round of
38 /* Operators defined in FIPS 180-2:4.1.2. */
39 #define Ch(x, y, z) ((x & y) ^ (~x & z))
40 #define Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
41 #define S0(x) (CYCLIC (x, 2) ^ CYCLIC (x, 13) ^ CYCLIC (x, 22))
42 #define S1(x) (CYCLIC (x, 6) ^ CYCLIC (x, 11) ^ CYCLIC (x, 25))
43 #define R0(x) (CYCLIC (x, 7) ^ CYCLIC (x, 18) ^ (x >> 3))
44 #define R1(x) (CYCLIC (x, 17) ^ CYCLIC (x, 19) ^ (x >> 10))
46 /* It is unfortunate that C does not provide an operator for
47 cyclic rotation. Hope the C compiler is smart enough. */
48 #define CYCLIC(w, s) ((w >> s) | (w << (32 - s)))
50 /* Compute the message schedule according to FIPS 180-2:6.2.2 step 2. */
51 for (unsigned int t = 0; t < 16; ++t)
56 for (unsigned int t = 16; t < 64; ++t)
57 W[t] = R1 (W[t - 2]) + W[t - 7] + R0 (W[t - 15]) + W[t - 16];
59 /* The actual computation according to FIPS 180-2:6.2.2 step 3. */
60 for (unsigned int t = 0; t < 64; ++t)
62 uint32_t T1 = h + S1 (e) + Ch (e, f, g) + K[t] + W[t];
63 uint32_t T2 = S0 (a) + Maj (a, b, c);
74 /* Add the starting values of the context according to FIPS 180-2:6.2.2
85 /* Prepare for the next round. */
89 /* Put checksum in context given as argument. */