fips_prf_openssl.c revision 8d520ff1dc2da35cdca849e982051b86468016d8 
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
22static 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
32int 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