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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "crypto/hmac.h" | |
6 | |
7 #include <CommonCrypto/CommonHMAC.h> | |
8 | |
9 #include "base/logging.h" | |
10 | |
11 namespace crypto { | |
12 | |
13 struct HMACPlatformData { | |
14 std::string key_; | |
15 }; | |
16 | |
17 HMAC::HMAC(HashAlgorithm hash_alg) | |
18 : hash_alg_(hash_alg), plat_(new HMACPlatformData()) { | |
19 // Only SHA-1 and SHA-256 hash algorithms are supported now. | |
20 DCHECK(hash_alg_ == SHA1 || hash_alg_ == SHA256); | |
21 } | |
22 | |
23 bool HMAC::Init(const unsigned char *key, int key_length) { | |
24 if (!plat_->key_.empty()) { | |
25 // Init must not be called more than once on the same HMAC object. | |
26 NOTREACHED(); | |
27 return false; | |
28 } | |
29 | |
30 plat_->key_.assign(reinterpret_cast<const char*>(key), key_length); | |
31 | |
32 return true; | |
33 } | |
34 | |
35 HMAC::~HMAC() { | |
36 // Zero out key copy. | |
37 plat_->key_.assign(plat_->key_.length(), std::string::value_type()); | |
38 plat_->key_.clear(); | |
39 plat_->key_.reserve(0); | |
40 } | |
41 | |
42 bool HMAC::Sign(const base::StringPiece& data, | |
43 unsigned char* digest, | |
44 int digest_length) const { | |
45 if (plat_->key_.empty()) { | |
46 // Init has not been called or has failed. | |
47 NOTREACHED(); | |
48 return false; | |
49 } | |
50 | |
51 CCHmacAlgorithm algorithm; | |
52 int algorithm_digest_length; | |
53 switch (hash_alg_) { | |
54 case SHA1: | |
55 algorithm = kCCHmacAlgSHA1; | |
56 algorithm_digest_length = CC_SHA1_DIGEST_LENGTH; | |
57 break; | |
58 case SHA256: | |
59 algorithm = kCCHmacAlgSHA256; | |
60 algorithm_digest_length = CC_SHA256_DIGEST_LENGTH; | |
61 break; | |
62 default: | |
63 NOTREACHED(); | |
64 return false; | |
65 } | |
66 | |
67 if (digest_length < algorithm_digest_length) { | |
68 NOTREACHED(); | |
69 return false; | |
70 } | |
71 | |
72 CCHmac(algorithm, | |
73 plat_->key_.data(), plat_->key_.length(), data.data(), data.length(), | |
74 digest); | |
75 | |
76 return true; | |
77 } | |
78 | |
79 } // namespace crypto | |
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