1/*
2 * Copyright (c) 2010 Apple Inc. All Rights Reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23
24#ifndef _CC_PBKDF_H_
25#define _CC_PBKDF_H_
26
27#include <string.h>
28#include <limits.h>
29#include <stdlib.h>
30#include <CommonCrypto/CommonDigest.h>
31#include <CommonCrypto/CommonHMAC.h>
32
33
34#ifdef __cplusplus
35extern "C" {
36#endif
37
38enum {
39 kCCPBKDF2 = 2,
40};
41
42
43typedef uint32_t CCPBKDFAlgorithm;
44
45
46enum {
47 kCCPRFHmacAlgSHA1 = 1,
48 kCCPRFHmacAlgSHA224 = 2,
49 kCCPRFHmacAlgSHA256 = 3,
50 kCCPRFHmacAlgSHA384 = 4,
51 kCCPRFHmacAlgSHA512 = 5,
52};
53
54
55typedef uint32_t CCPseudoRandomAlgorithm;
56
57/*
58
59 @function CCKeyDerivationPBKDF
60 @abstract Derive a key from a text password/passphrase
61
62 @param algorithm Currently only PBKDF2 is available via kCCPBKDF2
63 @param password The text password used as input to the derivation
64 function. The actual octets present in this string
65 will be used with no additional processing. It's
66 extremely important that the same encoding and
67 normalization be used each time this routine is
68 called if the same key is expected to be derived.
69 @param passwordLen The length of the text password in bytes.
70 @param salt The salt byte values used as input to the derivation
71 function. The pointer can be NULL, only when saltLen is zero.
72 @param saltLen The length of the salt in bytes. It can be zero.
73 @param prf The Pseudo Random Algorithm to use for the derivation
74 iterations.
75 @param rounds The number of rounds of the Pseudo Random Algorithm
76 to use. It cannot be zero.
77 @param derivedKey The resulting derived key produced by the function.
78 The space for this must be provided by the caller.
79 @param derivedKeyLen The expected length of the derived key in bytes. It cannot be zero.
80
81 @discussion The following values are used to designate the PRF:
82
83 * kCCPRFHmacAlgSHA1
84 * kCCPRFHmacAlgSHA224
85 * kCCPRFHmacAlgSHA256
86 * kCCPRFHmacAlgSHA384
87 * kCCPRFHmacAlgSHA512
88
89 @result kCCParamError can result from bad values for the password, salt,
90 and unwrapped key pointers as well as a bad value for the prf
91 function.
92
93 */
94
95int
96CCKeyDerivationPBKDF( CCPBKDFAlgorithm algorithm, const char *password, size_t passwordLen,
97 const uint8_t *salt, size_t saltLen,
98 CCPseudoRandomAlgorithm prf, unsigned rounds,
99 uint8_t *derivedKey, size_t derivedKeyLen)
100 API_AVAILABLE(macos(10.7), ios(5.0));
101
102/*
103 * All lengths are in bytes - not bits.
104 */
105
106/*
107
108 @function CCCalibratePBKDF
109 @abstract Determine the number of PRF rounds to use for a specific delay on
110 the current platform.
111 @param algorithm Currently only PBKDF2 is available via kCCPBKDF2
112 @param passwordLen The length of the text password in bytes.
113 @param saltLen The length of the salt in bytes. saltlen must be smaller than 133.
114 @param prf The Pseudo Random Algorithm to use for the derivation
115 iterations.
116 @param derivedKeyLen The expected length of the derived key in bytes.
117 @param msec The targetted duration we want to achieve for a key
118 derivation with these parameters.
119
120 @result the number of iterations to use for the desired processing time.
121 Returns a minimum of 10000 iterations (safety net, not a particularly recommended value)
122 The number of iterations is a trade-off of usability and security. If there is an error
123 the function returns (unsigned)(-1). The minimum return value is set to 10000.
124
125 */
126
127unsigned
128CCCalibratePBKDF(CCPBKDFAlgorithm algorithm, size_t passwordLen, size_t saltLen,
129 CCPseudoRandomAlgorithm prf, size_t derivedKeyLen, uint32_t msec)
130 API_AVAILABLE(macos(10.7), ios(5.0));
131
132#ifdef __cplusplus
133}
134#endif
135
136#endif /* _CC_PBKDF_H_ */