1214501Srpaulo/*
2214501Srpaulo * FIPS 186-2 PRF for internal crypto implementation
3214501Srpaulo * Copyright (c) 2006-2007, 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
11214501Srpaulo#include "common.h"
12214501Srpaulo#include "sha1.h"
13214501Srpaulo#include "sha1_i.h"
14214501Srpaulo#include "crypto.h"
15214501Srpaulo
16214501Srpaulo
17214501Srpauloint fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
18214501Srpaulo{
19214501Srpaulo	u8 xkey[64];
20214501Srpaulo	u32 t[5], _t[5];
21214501Srpaulo	int i, j, m, k;
22214501Srpaulo	u8 *xpos = x;
23214501Srpaulo	u32 carry;
24214501Srpaulo
25252726Srpaulo	if (seed_len < sizeof(xkey))
26252726Srpaulo		os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
27252726Srpaulo	else
28214501Srpaulo		seed_len = sizeof(xkey);
29214501Srpaulo
30214501Srpaulo	/* FIPS 186-2 + change notice 1 */
31214501Srpaulo
32214501Srpaulo	os_memcpy(xkey, seed, seed_len);
33214501Srpaulo	t[0] = 0x67452301;
34214501Srpaulo	t[1] = 0xEFCDAB89;
35214501Srpaulo	t[2] = 0x98BADCFE;
36214501Srpaulo	t[3] = 0x10325476;
37214501Srpaulo	t[4] = 0xC3D2E1F0;
38214501Srpaulo
39214501Srpaulo	m = xlen / 40;
40214501Srpaulo	for (j = 0; j < m; j++) {
41214501Srpaulo		/* XSEED_j = 0 */
42214501Srpaulo		for (i = 0; i < 2; i++) {
43214501Srpaulo			/* XVAL = (XKEY + XSEED_j) mod 2^b */
44214501Srpaulo
45214501Srpaulo			/* w_i = G(t, XVAL) */
46214501Srpaulo			os_memcpy(_t, t, 20);
47214501Srpaulo			SHA1Transform(_t, xkey);
48214501Srpaulo			_t[0] = host_to_be32(_t[0]);
49214501Srpaulo			_t[1] = host_to_be32(_t[1]);
50214501Srpaulo			_t[2] = host_to_be32(_t[2]);
51214501Srpaulo			_t[3] = host_to_be32(_t[3]);
52214501Srpaulo			_t[4] = host_to_be32(_t[4]);
53214501Srpaulo			os_memcpy(xpos, _t, 20);
54214501Srpaulo
55214501Srpaulo			/* XKEY = (1 + XKEY + w_i) mod 2^b */
56214501Srpaulo			carry = 1;
57214501Srpaulo			for (k = 19; k >= 0; k--) {
58214501Srpaulo				carry += xkey[k] + xpos[k];
59214501Srpaulo				xkey[k] = carry & 0xff;
60214501Srpaulo				carry >>= 8;
61214501Srpaulo			}
62214501Srpaulo
63214501Srpaulo			xpos += SHA1_MAC_LEN;
64214501Srpaulo		}
65214501Srpaulo		/* x_j = w_0|w_1 */
66214501Srpaulo	}
67214501Srpaulo
68214501Srpaulo	return 0;
69214501Srpaulo}
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