1 /* $OpenBSD: pbkdf2.c,v 1.1 2008/06/14 06:28:27 djm Exp $ */
4 * Copyright (c) 2008 Damien Bergamini <damien.bergamini@free.fr>
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
23 #define DS DigestState /* only to abbreviate SYNOPSIS */
24 #define SHA1_DIGEST_LENGTH 20
25 #define MIN(a,b) ((a < b) ? a : b)
28 * Password-Based Key Derivation Function 2 (PKCS #5 v2.0).
29 * Code based on IEEE Std 802.11-2007, Annex H.4.2.
32 pkcs5_pbkdf2(const unsigned char *pass, int pass_len, const unsigned char *salt, int salt_len,
33 unsigned char *key, int key_len, int rounds)
35 unsigned char *asalt, obuf[SHA1_DIGEST_LENGTH];
36 unsigned char d1[SHA1_DIGEST_LENGTH], d2[SHA1_DIGEST_LENGTH];
41 if (rounds < 1 || key_len == 0)
45 if ((asalt = malloc(salt_len + 4)) == nil)
48 memcpy(asalt, salt, salt_len);
50 for (count = 1; key_len > 0; count++) {
51 asalt[salt_len + 0] = (count >> 24) & 0xff;
52 asalt[salt_len + 1] = (count >> 16) & 0xff;
53 asalt[salt_len + 2] = (count >> 8) & 0xff;
54 asalt[salt_len + 3] = count & 0xff;
55 hmac_sha1(asalt, salt_len + 4, pass, pass_len, d1, nil);
56 memcpy(obuf, d1, sizeof(obuf));
58 for (i = 1; i < rounds; i++) {
59 hmac_sha1(d1, sizeof(d1), pass, pass_len, d2, nil);
60 memcpy(d1, d2, sizeof(d1));
61 for (j = 0; j < sizeof(obuf); j++)
65 r = MIN(key_len, SHA1_DIGEST_LENGTH);
70 memset(asalt, 0, salt_len + 4);
72 memset(d1, 0, sizeof(d1));
73 memset(d2, 0, sizeof(d2));
74 memset(obuf, 0, sizeof(obuf));