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 <openssl/hmac.h> 8 9 #include <algorithm> 10 #include <vector> 11 12 #include "base/logging.h" 13 #include "base/memory/scoped_ptr.h" 14 #include "base/stl_util.h" 15 #include "crypto/openssl_util.h" 16 17 namespace crypto { 18 19 struct HMACPlatformData { 20 std::vector<unsigned char> key; 21 }; 22 23 HMAC::HMAC(HashAlgorithm hash_alg) 24 : hash_alg_(hash_alg), plat_(new HMACPlatformData()) { 25 // Only SHA-1 and SHA-256 hash algorithms are supported now. 26 DCHECK(hash_alg_ == SHA1 || hash_alg_ == SHA256); 27 } 28 29 bool HMAC::Init(const unsigned char* key, size_t key_length) { 30 // Init must not be called more than once on the same HMAC object. 31 DCHECK(plat_->key.empty()); 32 33 plat_->key.assign(key, key + key_length); 34 return true; 35 } 36 37 HMAC::~HMAC() { 38 // Zero out key copy. 39 plat_->key.assign(plat_->key.size(), 0); 40 STLClearObject(&plat_->key); 41 } 42 43 bool HMAC::Sign(const base::StringPiece& data, 44 unsigned char* digest, 45 size_t digest_length) const { 46 DCHECK(!plat_->key.empty()); // Init must be called before Sign. 47 48 ScopedOpenSSLSafeSizeBuffer<EVP_MAX_MD_SIZE> result(digest, digest_length); 49 return ::HMAC(hash_alg_ == SHA1 ? EVP_sha1() : EVP_sha256(), 50 &plat_->key[0], plat_->key.size(), 51 reinterpret_cast<const unsigned char*>(data.data()), 52 data.size(), 53 result.safe_buffer(), NULL); 54 } 55 56 } // namespace crypto 57
