1214501Srpaulo/*
2214501Srpaulo * FIPS 186-2 PRF for libcrypto
3214501Srpaulo * Copyright (c) 2004-2005, Jouni Malinen <j@w1.fi>
4214501Srpaulo *
5252726Srpaulo * This software may be distributed under the terms of the BSD license.
6252726Srpaulo * See README for more details.
7214501Srpaulo */
8214501Srpaulo
9214501Srpaulo#include "includes.h"
10214501Srpaulo#include <openssl/sha.h>
11214501Srpaulo
12214501Srpaulo#include "common.h"
13214501Srpaulo#include "crypto.h"
14214501Srpaulo
15214501Srpaulo
16214501Srpaulostatic void sha1_transform(u8 *state, const u8 data[64])
17214501Srpaulo{
18214501Srpaulo	SHA_CTX context;
19214501Srpaulo	os_memset(&context, 0, sizeof(context));
20214501Srpaulo	os_memcpy(&context.h0, state, 5 * 4);
21214501Srpaulo	SHA1_Transform(&context, data);
22214501Srpaulo	os_memcpy(state, &context.h0, 5 * 4);
23214501Srpaulo}
24214501Srpaulo
25214501Srpaulo
26214501Srpauloint fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
27214501Srpaulo{
28214501Srpaulo	u8 xkey[64];
29214501Srpaulo	u32 t[5], _t[5];
30214501Srpaulo	int i, j, m, k;
31214501Srpaulo	u8 *xpos = x;
32214501Srpaulo	u32 carry;
33214501Srpaulo
34252726Srpaulo	if (seed_len < sizeof(xkey))
35252726Srpaulo		os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
36252726Srpaulo	else
37214501Srpaulo		seed_len = sizeof(xkey);
38214501Srpaulo
39214501Srpaulo	/* FIPS 186-2 + change notice 1 */
40214501Srpaulo
41214501Srpaulo	os_memcpy(xkey, seed, seed_len);
42214501Srpaulo	t[0] = 0x67452301;
43214501Srpaulo	t[1] = 0xEFCDAB89;
44214501Srpaulo	t[2] = 0x98BADCFE;
45214501Srpaulo	t[3] = 0x10325476;
46214501Srpaulo	t[4] = 0xC3D2E1F0;
47214501Srpaulo
48214501Srpaulo	m = xlen / 40;
49214501Srpaulo	for (j = 0; j < m; j++) {
50214501Srpaulo		/* XSEED_j = 0 */
51214501Srpaulo		for (i = 0; i < 2; i++) {
52214501Srpaulo			/* XVAL = (XKEY + XSEED_j) mod 2^b */
53214501Srpaulo
54214501Srpaulo			/* w_i = G(t, XVAL) */
55214501Srpaulo			os_memcpy(_t, t, 20);
56214501Srpaulo			sha1_transform((u8 *) _t, xkey);
57214501Srpaulo			_t[0] = host_to_be32(_t[0]);
58214501Srpaulo			_t[1] = host_to_be32(_t[1]);
59214501Srpaulo			_t[2] = host_to_be32(_t[2]);
60214501Srpaulo			_t[3] = host_to_be32(_t[3]);
61214501Srpaulo			_t[4] = host_to_be32(_t[4]);
62214501Srpaulo			os_memcpy(xpos, _t, 20);
63214501Srpaulo
64214501Srpaulo			/* XKEY = (1 + XKEY + w_i) mod 2^b */
65214501Srpaulo			carry = 1;
66214501Srpaulo			for (k = 19; k >= 0; k--) {
67214501Srpaulo				carry += xkey[k] + xpos[k];
68214501Srpaulo				xkey[k] = carry & 0xff;
69214501Srpaulo				carry >>= 8;
70214501Srpaulo			}
71214501Srpaulo
72214501Srpaulo			xpos += 20;
73214501Srpaulo		}
74214501Srpaulo		/* x_j = w_0|w_1 */
75214501Srpaulo	}
76214501Srpaulo
77214501Srpaulo	return 0;
78214501Srpaulo}
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