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