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Diffstat (limited to 'recipes/shasum/files/sha256.c')
| -rw-r--r-- | recipes/shasum/files/sha256.c | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/recipes/shasum/files/sha256.c b/recipes/shasum/files/sha256.c new file mode 100644 index 0000000000..e2ee2c6b4e --- /dev/null +++ b/recipes/shasum/files/sha256.c @@ -0,0 +1,322 @@ +/* sha256.h + * + * The sha256 hash function. + */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2001 Niels Möller + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or (at your option) any later version. + * + * The nettle library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the nettle library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. + */ + +/* Modelled after the sha1.c code by Peter Gutmann. */ + +#include "mhash_sha256.h" +#include <stdlib.h> +#include <string.h> + + +#ifndef EXTRACT_UCHAR +#define EXTRACT_UCHAR(p) (*(unsigned char *)(p)) +#endif + +#define STRING2INT(s) ((((((EXTRACT_UCHAR(s) << 8) \ + | EXTRACT_UCHAR(s+1)) << 8) \ + | EXTRACT_UCHAR(s+2)) << 8) \ + | EXTRACT_UCHAR(s+3)) + +/* This has been modified in order to fit in mhash. + * --nmav. + */ + +/* A block, treated as a sequence of 32-bit words. */ +#define SHA256_DATA_LENGTH 16 + +#define ROTR(n,x) ((x)>>(n) | ((x)<<(32-(n)))) +#define SHR(n,x) ((x)>>(n)) + +/* The SHA256 functions. The Choice function is the same as the SHA1 + function f1, and the majority function is the same as the SHA1 f3 + function. They can be optimized to save one boolean operation each + - thanks to Rich Schroeppel, rcs@cs.arizona.edu for discovering + this */ + +/* #define Choice(x,y,z) ( ( (x) & (y) ) | ( ~(x) & (z) ) ) */ +#define Choice(x,y,z) ( (z) ^ ( (x) & ( (y) ^ (z) ) ) ) +/* #define Majority(x,y,z) ( ((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)) ) */ +#define Majority(x,y,z) ( ((x) & (y)) ^ ((z) & ((x) ^ (y))) ) + +#define S0(x) (ROTR(2,(x)) ^ ROTR(13,(x)) ^ ROTR(22,(x))) +#define S1(x) (ROTR(6,(x)) ^ ROTR(11,(x)) ^ ROTR(25,(x))) + +#define s0(x) (ROTR(7,(x)) ^ ROTR(18,(x)) ^ SHR(3,(x))) +#define s1(x) (ROTR(17,(x)) ^ ROTR(19,(x)) ^ SHR(10,(x))) + +/* Generated by the shadata program. */ +static const word32 K[64] = { + 0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL, + 0x3956c25bUL, 0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL, + 0xd807aa98UL, 0x12835b01UL, 0x243185beUL, 0x550c7dc3UL, + 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL, 0xc19bf174UL, + 0xe49b69c1UL, 0xefbe4786UL, 0xfc19dc6UL, 0x240ca1ccUL, + 0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL, + 0x983e5152UL, 0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL, + 0xc6e00bf3UL, 0xd5a79147UL, 0x6ca6351UL, 0x14292967UL, + 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL, 0x53380d13UL, + 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL, + 0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL, + 0xd192e819UL, 0xd6990624UL, 0xf40e3585UL, 0x106aa070UL, + 0x19a4c116UL, 0x1e376c08UL, 0x2748774cUL, 0x34b0bcb5UL, + 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL, 0x682e6ff3UL, + 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL, + 0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL, +}; + +/* The initial expanding function. The hash function is defined over an + 64-word expanded input array W, where the first 16 are copies of the input + data, and the remaining 64 are defined by + + W[ t ] = s1(W[t-2] + W[t-7] + s0(W[i-15] + W[i-16] + + This implementation generates these values on the fly in a circular + buffer - thanks to Colin Plumb, colin@nyx10.cs.du.edu for this + optimization. +*/ + +#define EXPAND(W,i) \ +( W[(i) & 15 ] += (s1(W[((i)-2) & 15]) + W[((i)-7) & 15] + s0(W[((i)-15) & 15])) ) + +/* The prototype SHA sub-round. The fundamental sub-round is: + + T1 = h + S1(e) + Choice(e,f,g) + K[t] + W[t] + T2 = S0(a) + Majority(a,b,c) + a' = T1+T2 + b' = a + c' = b + d' = c + e' = d + T1 + f' = e + g' = f + h' = g + + but this is implemented by unrolling the loop 8 times and renaming + the variables + ( h, a, b, c, d, e, f, g ) = ( a, b, c, d, e, f, g, h ) each + iteration. This code is then replicated 8, using the next 8 values + from the W[] array each time */ + +/* FIXME: We can probably reorder this to optimize away at least one + * of T1 and T2. It's crucial that DATA is only used once, as that + * argument will have side effects. */ +#define ROUND(a,b,c,d,e,f,g,h,k,data) do { \ + word32 T1 = h + S1(e) + Choice(e,f,g) + k + data; \ + word32 T2 = S0(a) + Majority(a,b,c); \ + d += T1; \ + h = T1 + T2; \ +} while (0) + +/* Initialize the SHA values */ + +void sha256_init(struct sha256_ctx *ctx) +{ + /* Initial values, also generated by the shadata program. */ + static const word32 H0[_SHA256_DIGEST_LENGTH] = { + 0x6a09e667UL, 0xbb67ae85UL, 0x3c6ef372UL, 0xa54ff53aUL, + 0x510e527fUL, 0x9b05688cUL, 0x1f83d9abUL, 0x5be0cd19UL, + }; + + memcpy(ctx->state, H0, sizeof(H0)); + + /* Initialize bit count */ + ctx->count_low = ctx->count_high = 0; + + /* Initialize buffer */ + ctx->index = 0; +} + +/* Perform the SHA transformation. Note that this code, like MD5, seems to + break some optimizing compilers due to the complexity of the expressions + and the size of the basic block. It may be necessary to split it into + sections, e.g. based on the four subrounds + + Note that this function destroys the data area */ + +static void sha256_transform(word32 * state, word32 * data) +{ + word32 A, B, C, D, E, F, G, H; /* Local vars */ + unsigned i; + const word32 *k; + word32 *d; + + /* Set up first buffer and local data buffer */ + A = state[0]; + B = state[1]; + C = state[2]; + D = state[3]; + E = state[4]; + F = state[5]; + G = state[6]; + H = state[7]; + + /* Heavy mangling */ + /* First 16 subrounds that act on the original data */ + + for (i = 0, k = K, d = data; i < 16; i += 8, k += 8, d += 8) { + ROUND(A, B, C, D, E, F, G, H, k[0], d[0]); + ROUND(H, A, B, C, D, E, F, G, k[1], d[1]); + ROUND(G, H, A, B, C, D, E, F, k[2], d[2]); + ROUND(F, G, H, A, B, C, D, E, k[3], d[3]); + ROUND(E, F, G, H, A, B, C, D, k[4], d[4]); + ROUND(D, E, F, G, H, A, B, C, k[5], d[5]); + ROUND(C, D, E, F, G, H, A, B, k[6], d[6]); + ROUND(B, C, D, E, F, G, H, A, k[7], d[7]); + } + + for (; i < 64; i += 16, k += 16) { + ROUND(A, B, C, D, E, F, G, H, k[0], EXPAND(data, 0)); + ROUND(H, A, B, C, D, E, F, G, k[1], EXPAND(data, 1)); + ROUND(G, H, A, B, C, D, E, F, k[2], EXPAND(data, 2)); + ROUND(F, G, H, A, B, C, D, E, k[3], EXPAND(data, 3)); + ROUND(E, F, G, H, A, B, C, D, k[4], EXPAND(data, 4)); + ROUND(D, E, F, G, H, A, B, C, k[5], EXPAND(data, 5)); + ROUND(C, D, E, F, G, H, A, B, k[6], EXPAND(data, 6)); + ROUND(B, C, D, E, F, G, H, A, k[7], EXPAND(data, 7)); + ROUND(A, B, C, D, E, F, G, H, k[8], EXPAND(data, 8)); + ROUND(H, A, B, C, D, E, F, G, k[9], EXPAND(data, 9)); + ROUND(G, H, A, B, C, D, E, F, k[10], EXPAND(data, 10)); + ROUND(F, G, H, A, B, C, D, E, k[11], EXPAND(data, 11)); + ROUND(E, F, G, H, A, B, C, D, k[12], EXPAND(data, 12)); + ROUND(D, E, F, G, H, A, B, C, k[13], EXPAND(data, 13)); + ROUND(C, D, E, F, G, H, A, B, k[14], EXPAND(data, 14)); + ROUND(B, C, D, E, F, G, H, A, k[15], EXPAND(data, 15)); + } + + /* Update state */ + state[0] += A; + state[1] += B; + state[2] += C; + state[3] += D; + state[4] += E; + state[5] += F; + state[6] += G; + state[7] += H; +} + +static void sha256_block(struct sha256_ctx *ctx, const byte * block) +{ + word32 data[SHA256_DATA_LENGTH]; + int i; + + /* Update block count */ + if (!++ctx->count_low) + ++ctx->count_high; + + /* Endian independent conversion */ + for (i = 0; i < SHA256_DATA_LENGTH; i++, block += 4) + data[i] = STRING2INT(block); + + sha256_transform(ctx->state, data); +} + +void +sha256_update(struct sha256_ctx *ctx, const byte * buffer, unsigned length) +{ + if (ctx->index) { /* Try to fill partial block */ + unsigned left = SHA256_DATA_SIZE - ctx->index; + if (length < left) { + memcpy(ctx->block + ctx->index, buffer, length); + ctx->index += length; + return; /* Finished */ + } else { + memcpy(ctx->block + ctx->index, buffer, left); + sha256_block(ctx, ctx->block); + buffer += left; + length -= left; + } + } + while (length >= SHA256_DATA_SIZE) { + sha256_block(ctx, buffer); + buffer += SHA256_DATA_SIZE; + length -= SHA256_DATA_SIZE; + } + /* Buffer leftovers */ + /* NOTE: The corresponding sha1 code checks for the special case length == 0. + * That seems supoptimal, as I suspect it increases the number of branches. */ + + memcpy(ctx->block, buffer, length); + ctx->index = length; +} + +/* Final wrapup - pad to SHA1_DATA_SIZE-byte boundary with the bit pattern + 1 0* (64-bit count of bits processed, MSB-first) */ + +void sha256_final(struct sha256_ctx *ctx) +{ + word32 data[SHA256_DATA_LENGTH]; + int i; + int words; + + i = ctx->index; + + /* Set the first char of padding to 0x80. This is safe since there is + always at least one byte free */ + +/* assert(i < SHA256_DATA_SIZE); + */ + ctx->block[i++] = 0x80; + + /* Fill rest of word */ + for (; i & 3; i++) + ctx->block[i] = 0; + + /* i is now a multiple of the word size 4 */ + words = i >> 2; + for (i = 0; i < words; i++) + data[i] = STRING2INT(ctx->block + 4 * i); + + if (words > (SHA256_DATA_LENGTH - 2)) { /* No room for length in this block. Process it and + * pad with another one */ + for (i = words; i < SHA256_DATA_LENGTH; i++) + data[i] = 0; + sha256_transform(ctx->state, data); + for (i = 0; i < (SHA256_DATA_LENGTH - 2); i++) + data[i] = 0; + } else + for (i = words; i < SHA256_DATA_LENGTH - 2; i++) + data[i] = 0; + + /* There are 512 = 2^9 bits in one block */ + data[SHA256_DATA_LENGTH - 2] = + (ctx->count_high << 9) | (ctx->count_low >> 23); + data[SHA256_DATA_LENGTH - 1] = + (ctx->count_low << 9) | (ctx->index << 3); + sha256_transform(ctx->state, data); +} + +void sha256_digest(const struct sha256_ctx *ctx, byte * s) +{ + int i; + + if (s!=NULL) + for (i = 0; i < _SHA256_DIGEST_LENGTH; i++) { + *s++ = ctx->state[i] >> 24; + *s++ = 0xff & (ctx->state[i] >> 16); + *s++ = 0xff & (ctx->state[i] >> 8); + *s++ = 0xff & ctx->state[i]; + } +} + |