sha256.c (3049B)
1 /* sha256.c - SHA-256 (FIPS 180-4) en un solo bloque de memoria. */ 2 #include <string.h> 3 #include "sha256.h" 4 5 static const uint32_t K[64] = { 6 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 7 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 8 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 9 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 10 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 11 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 12 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 13 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2 14 }; 15 16 #define ROR(x, n) (((x) >> (n)) | ((x) << (32 - (n)))) 17 18 static void block(uint32_t h[8], const uint8_t *p) 19 { 20 uint32_t w[64]; 21 for (int i = 0; i < 16; i++) 22 w[i] = (uint32_t)p[4 * i] << 24 | (uint32_t)p[4 * i + 1] << 16 | (uint32_t)p[4 * i + 2] << 8 | p[4 * i + 3]; 23 for (int i = 16; i < 64; i++) { 24 uint32_t s0 = ROR(w[i - 15], 7) ^ ROR(w[i - 15], 18) ^ (w[i - 15] >> 3); 25 uint32_t s1 = ROR(w[i - 2], 17) ^ ROR(w[i - 2], 19) ^ (w[i - 2] >> 10); 26 w[i] = w[i - 16] + s0 + w[i - 7] + s1; 27 } 28 uint32_t a = h[0], b = h[1], c = h[2], d = h[3], e = h[4], f = h[5], g = h[6], k = h[7]; 29 for (int i = 0; i < 64; i++) { 30 uint32_t t1 = k + (ROR(e, 6) ^ ROR(e, 11) ^ ROR(e, 25)) + ((e & f) ^ (~e & g)) + K[i] + w[i]; 31 uint32_t t2 = (ROR(a, 2) ^ ROR(a, 13) ^ ROR(a, 22)) + ((a & b) ^ (a & c) ^ (b & c)); 32 k = g; g = f; f = e; e = d + t1; d = c; c = b; b = a; a = t1 + t2; 33 } 34 h[0] += a; h[1] += b; h[2] += c; h[3] += d; h[4] += e; h[5] += f; h[6] += g; h[7] += k; 35 } 36 37 void sha256(const void *data, size_t len, uint8_t out[32]) 38 { 39 uint32_t h[8] = { 0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19 }; 40 const uint8_t *p = data; 41 size_t n = len; 42 for (; n >= 64; n -= 64, p += 64) block(h, p); 43 uint8_t tail[128]; 44 memset(tail, 0, sizeof tail); 45 memcpy(tail, p, n); 46 tail[n] = 0x80; 47 int tl = n + 9 > 64 ? 128 : 64; 48 uint64_t bits = (uint64_t)len * 8; 49 for (int i = 0; i < 8; i++) tail[tl - 1 - i] = (uint8_t)(bits >> (8 * i)); 50 block(h, tail); 51 if (tl == 128) block(h, tail + 64); 52 for (int i = 0; i < 8; i++) { 53 out[4 * i] = (uint8_t)(h[i] >> 24); out[4 * i + 1] = (uint8_t)(h[i] >> 16); 54 out[4 * i + 2] = (uint8_t)(h[i] >> 8); out[4 * i + 3] = (uint8_t)h[i]; 55 } 56 } 57 58 void sha256_hex(const void *data, size_t len, char out[65]) 59 { 60 static const char HEX[] = "0123456789abcdef"; 61 uint8_t d[32]; 62 sha256(data, len, d); 63 for (int i = 0; i < 32; i++) { out[2 * i] = HEX[d[i] >> 4]; out[2 * i + 1] = HEX[d[i] & 15]; } 64 out[64] = 0; 65 }