1 /* 2 * FIPS 186-2 PRF for internal crypto implementation 3 * Copyright (c) 2006-2007, Jouni Malinen <j@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 11 #include "common.h" 12 #include "sha1.h" 13 #include "sha1_i.h" 14 #include "crypto.h" 15 16 17 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen) 18 { 19 u8 xkey[64]; 20 u32 t[5], _t[5]; 21 int i, j, m, k; 22 u8 *xpos = x; 23 u32 carry; 24 25 if (seed_len < sizeof(xkey)) 26 os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len); 27 else 28 seed_len = sizeof(xkey); 29 30 /* FIPS 186-2 + change notice 1 */ 31 32 os_memcpy(xkey, seed, seed_len); 33 t[0] = 0x67452301; 34 t[1] = 0xEFCDAB89; 35 t[2] = 0x98BADCFE; 36 t[3] = 0x10325476; 37 t[4] = 0xC3D2E1F0; 38 39 m = xlen / 40; 40 for (j = 0; j < m; j++) { 41 /* XSEED_j = 0 */ 42 for (i = 0; i < 2; i++) { 43 /* XVAL = (XKEY + XSEED_j) mod 2^b */ 44 45 /* w_i = G(t, XVAL) */ 46 os_memcpy(_t, t, 20); 47 SHA1Transform(_t, xkey); 48 _t[0] = host_to_be32(_t[0]); 49 _t[1] = host_to_be32(_t[1]); 50 _t[2] = host_to_be32(_t[2]); 51 _t[3] = host_to_be32(_t[3]); 52 _t[4] = host_to_be32(_t[4]); 53 os_memcpy(xpos, _t, 20); 54 55 /* XKEY = (1 + XKEY + w_i) mod 2^b */ 56 carry = 1; 57 for (k = 19; k >= 0; k--) { 58 carry += xkey[k] + xpos[k]; 59 xkey[k] = carry & 0xff; 60 carry >>= 8; 61 } 62 63 xpos += SHA1_MAC_LEN; 64 } 65 /* x_j = w_0|w_1 */ 66 } 67 68 return 0; 69 } 70