104 lines
2.6 KiB
C
104 lines
2.6 KiB
C
/*
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* SHA transform algorithm, originally taken from code written by
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* Peter Gutmann, and placed in the public domain.
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*/
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static uint32_t
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rol32(uint32_t word, int shift)
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{
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return (word << shift) | (word >> (32 - shift));
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}
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/* The SHA f()-functions. */
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#define f1(x,y,z) (z ^ (x & (y ^ z))) /* x ? y : z */
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#define f2(x,y,z) (x ^ y ^ z) /* XOR */
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#define f3(x,y,z) ((x & y) + (z & (x ^ y))) /* majority */
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/* The SHA Mysterious Constants */
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#define K1 0x5A827999L /* Rounds 0-19: sqrt(2) * 2^30 */
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#define K2 0x6ED9EBA1L /* Rounds 20-39: sqrt(3) * 2^30 */
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#define K3 0x8F1BBCDCL /* Rounds 40-59: sqrt(5) * 2^30 */
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#define K4 0xCA62C1D6L /* Rounds 60-79: sqrt(10) * 2^30 */
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/**
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* sha_transform - single block SHA1 transform
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*
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* @digest: 160 bit digest to update
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* @data: 512 bits of data to hash
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* @W: 80 words of workspace (see note)
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*
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* This function generates a SHA1 digest for a single 512-bit block.
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* Be warned, it does not handle padding and message digest, do not
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* confuse it with the full FIPS 180-1 digest algorithm for variable
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* length messages.
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*
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* Note: If the hash is security sensitive, the caller should be sure
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* to clear the workspace. This is left to the caller to avoid
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* unnecessary clears between chained hashing operations.
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*/
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static void sha_transform(uint32_t *digest, const unsigned char *in, uint32_t *W)
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{
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uint32_t a, b, c, d, e, t, i;
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for (i = 0; i < 16; i++) {
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int ofs = 4 * i;
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/* word load/store may be unaligned here, so use bytes instead */
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W[i] =
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(in[ofs+0] << 24) |
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(in[ofs+1] << 16) |
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(in[ofs+2] << 8) |
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in[ofs+3];
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}
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for (i = 0; i < 64; i++)
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W[i+16] = rol32(W[i+13] ^ W[i+8] ^ W[i+2] ^ W[i], 1);
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a = digest[0];
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b = digest[1];
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c = digest[2];
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d = digest[3];
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e = digest[4];
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for (i = 0; i < 20; i++) {
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t = f1(b, c, d) + K1 + rol32(a, 5) + e + W[i];
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e = d; d = c; c = rol32(b, 30); b = a; a = t;
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}
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for (; i < 40; i ++) {
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t = f2(b, c, d) + K2 + rol32(a, 5) + e + W[i];
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e = d; d = c; c = rol32(b, 30); b = a; a = t;
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}
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for (; i < 60; i ++) {
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t = f3(b, c, d) + K3 + rol32(a, 5) + e + W[i];
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e = d; d = c; c = rol32(b, 30); b = a; a = t;
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}
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for (; i < 80; i ++) {
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t = f2(b, c, d) + K4 + rol32(a, 5) + e + W[i];
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e = d; d = c; c = rol32(b, 30); b = a; a = t;
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}
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digest[0] += a;
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digest[1] += b;
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digest[2] += c;
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digest[3] += d;
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digest[4] += e;
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}
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/**
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* sha_init - initialize the vectors for a SHA1 digest
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* @buf: vector to initialize
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*/
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static void sha_init(uint32_t *buf)
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{
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buf[0] = 0x67452301;
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buf[1] = 0xefcdab89;
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buf[2] = 0x98badcfe;
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buf[3] = 0x10325476;
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buf[4] = 0xc3d2e1f0;
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}
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