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 11namespace crypto { 12 13struct HMACPlatformData { 14 std::string key_; 15}; 16 17HMAC::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 23bool 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 35HMAC::~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 42bool HMAC::Sign(const std::string& data, 43 unsigned char* digest, 44 int digest_length) { 45 CCHmacAlgorithm algorithm; 46 int algorithm_digest_length; 47 switch (hash_alg_) { 48 case SHA1: 49 algorithm = kCCHmacAlgSHA1; 50 algorithm_digest_length = CC_SHA1_DIGEST_LENGTH; 51 break; 52 case SHA256: 53 algorithm = kCCHmacAlgSHA256; 54 algorithm_digest_length = CC_SHA256_DIGEST_LENGTH; 55 break; 56 default: 57 NOTREACHED(); 58 return false; 59 } 60 61 if (digest_length < algorithm_digest_length) { 62 NOTREACHED(); 63 return false; 64 } 65 66 CCHmac(algorithm, 67 plat_->key_.data(), plat_->key_.length(), data.data(), data.length(), 68 digest); 69 70 return true; 71} 72 73} // namespace crypto 74