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