1 /* 2 * FIPS 186-2 PRF for libcrypto 3 * Copyright (c) 2004-2005, Jouni Malinen <j (at) w1.fi> 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9 #include "includes.h" 10 #include <openssl/sha.h> 11 12 #include "common.h" 13 #include "crypto.h" 14 15 16 static void sha1_transform(u32 *state, const u8 data[64]) 17 { 18 SHA_CTX context; 19 os_memset(&context, 0, sizeof(context)); 20 context.h0 = state[0]; 21 context.h1 = state[1]; 22 context.h2 = state[2]; 23 context.h3 = state[3]; 24 context.h4 = state[4]; 25 SHA1_Transform(&context, data); 26 state[0] = context.h0; 27 state[1] = context.h1; 28 state[2] = context.h2; 29 state[3] = context.h3; 30 state[4] = context.h4; 31 } 32 33 34 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen) 35 { 36 u8 xkey[64]; 37 u32 t[5], _t[5]; 38 int i, j, m, k; 39 u8 *xpos = x; 40 u32 carry; 41 42 if (seed_len < sizeof(xkey)) 43 os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len); 44 else 45 seed_len = sizeof(xkey); 46 47 /* FIPS 186-2 + change notice 1 */ 48 49 os_memcpy(xkey, seed, seed_len); 50 t[0] = 0x67452301; 51 t[1] = 0xEFCDAB89; 52 t[2] = 0x98BADCFE; 53 t[3] = 0x10325476; 54 t[4] = 0xC3D2E1F0; 55 56 m = xlen / 40; 57 for (j = 0; j < m; j++) { 58 /* XSEED_j = 0 */ 59 for (i = 0; i < 2; i++) { 60 /* XVAL = (XKEY + XSEED_j) mod 2^b */ 61 62 /* w_i = G(t, XVAL) */ 63 os_memcpy(_t, t, 20); 64 sha1_transform(_t, xkey); 65 _t[0] = host_to_be32(_t[0]); 66 _t[1] = host_to_be32(_t[1]); 67 _t[2] = host_to_be32(_t[2]); 68 _t[3] = host_to_be32(_t[3]); 69 _t[4] = host_to_be32(_t[4]); 70 os_memcpy(xpos, _t, 20); 71 72 /* XKEY = (1 + XKEY + w_i) mod 2^b */ 73 carry = 1; 74 for (k = 19; k >= 0; k--) { 75 carry += xkey[k] + xpos[k]; 76 xkey[k] = carry & 0xff; 77 carry >>= 8; 78 } 79 80 xpos += 20; 81 } 82 /* x_j = w_0|w_1 */ 83 } 84 85 return 0; 86 } 87
