package/ead/src/sha1.c

   1 /*
   2  * SHA transform algorithm, originally taken from code written by
   3  * Peter Gutmann, and placed in the public domain.
   4  */
   5
   6 static  uint32_t
   7 rol32(uint32_t word, int shift)
   8 {
   9         return (word << shift) | (word >> (32 - shift));
  10 }
  11
  12 /* The SHA f()-functions.  */
  13
  14 #define f1(x,y,z)   (z ^ (x & (y ^ z)))         /* x ? y : z */
  15 #define f2(x,y,z)   (x ^ y ^ z)                 /* XOR */
  16 #define f3(x,y,z)   ((x & y) + (z & (x ^ y)))   /* majority */
  17
  18 /* The SHA Mysterious Constants */
  19
  20 #define K1  0x5A827999L                 /* Rounds  0-19: sqrt(2) * 2^30 */
  21 #define K2  0x6ED9EBA1L                 /* Rounds 20-39: sqrt(3) * 2^30 */
  22 #define K3  0x8F1BBCDCL                 /* Rounds 40-59: sqrt(5) * 2^30 */
  23 #define K4  0xCA62C1D6L                 /* Rounds 60-79: sqrt(10) * 2^30 */
  24
  25 /**
  26  * sha_transform - single block SHA1 transform
  27  *
  28  * @digest: 160 bit digest to update
  29  * @data:   512 bits of data to hash
  30  * @W:      80 words of workspace (see note)
  31  *
  32  * This function generates a SHA1 digest for a single 512-bit block.
  33  * Be warned, it does not handle padding and message digest, do not
  34  * confuse it with the full FIPS 180-1 digest algorithm for variable
  35  * length messages.
  36  *
  37  * Note: If the hash is security sensitive, the caller should be sure
  38  * to clear the workspace. This is left to the caller to avoid
  39  * unnecessary clears between chained hashing operations.
  40  */
  41 static void sha_transform(uint32_t *digest, const unsigned char *in, uint32_t *W)
  42 {
  43         uint32_t a, b, c, d, e, t, i;
  44
  45         for (i = 0; i < 16; i++) {
  46                 int ofs = 4 * i;
  47
  48                 /* word load/store may be unaligned here, so use bytes instead */
  49                 W[i] =
  50                         (in[ofs+0] << 24) |
  51                         (in[ofs+1] << 16) |
  52                         (in[ofs+2] << 8) |
  53                          in[ofs+3];
  54         }
  55
  56         for (i = 0; i < 64; i++)
  57                 W[i+16] = rol32(W[i+13] ^ W[i+8] ^ W[i+2] ^ W[i], 1);
  58
  59         a = digest[0];
  60         b = digest[1];
  61         c = digest[2];
  62         d = digest[3];
  63         e = digest[4];
  64
  65         for (i = 0; i < 20; i++) {
  66                 t = f1(b, c, d) + K1 + rol32(a, 5) + e + W[i];
  67                 e = d; d = c; c = rol32(b, 30); b = a; a = t;
  68         }
  69
  70         for (; i < 40; i ++) {
  71                 t = f2(b, c, d) + K2 + rol32(a, 5) + e + W[i];
  72                 e = d; d = c; c = rol32(b, 30); b = a; a = t;
  73         }
  74
  75         for (; i < 60; i ++) {
  76                 t = f3(b, c, d) + K3 + rol32(a, 5) + e + W[i];
  77                 e = d; d = c; c = rol32(b, 30); b = a; a = t;
  78         }
  79
  80         for (; i < 80; i ++) {
  81                 t = f2(b, c, d) + K4 + rol32(a, 5) + e + W[i];
  82                 e = d; d = c; c = rol32(b, 30); b = a; a = t;
  83         }
  84
  85         digest[0] += a;
  86         digest[1] += b;
  87         digest[2] += c;
  88         digest[3] += d;
  89         digest[4] += e;
  90 }
  91
  92 /**
  93  * sha_init - initialize the vectors for a SHA1 digest
  94  * @buf: vector to initialize
  95  */
  96 static void sha_init(uint32_t *buf)
  97 {
  98         buf[0] = 0x67452301;
  99         buf[1] = 0xefcdab89;
 100         buf[2] = 0x98badcfe;
 101         buf[3] = 0x10325476;
 102         buf[4] = 0xc3d2e1f0;
 103 }
 104