base/hmac_mac.cc

   1 // Copyright (c) 2008 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 "base/hmac.h"
   6
   7 #include <CommonCrypto/CommonHMAC.h>
   8
   9 #include "base/logging.h"
  10
  11 namespace base {
  12
  13 struct HMACPlatformData {
  14   std::string key_;
  15 };
  16
  17 HMAC::HMAC(HashAlgorithm hash_alg, const unsigned char* key, int key_length)
  18     : hash_alg_(hash_alg), plat_(new HMACPlatformData()) {
  19   plat_->key_.assign(reinterpret_cast<const char*>(key), key_length);
  20 }
  21
  22 HMAC::~HMAC() {
  23   // Zero out key copy.
  24   plat_->key_.assign(plat_->key_.length(), std::string::value_type());
  25   plat_->key_.clear();
  26   plat_->key_.reserve(0);
  27
  28   delete plat_;
  29 }
  30
  31 bool HMAC::Sign(const std::string& data,
  32                 unsigned char* digest,
  33                 int digest_length) {
  34   CCHmacAlgorithm algorithm;
  35   int algorithm_digest_length;
  36   switch (hash_alg_) {
  37     case SHA1:
  38       algorithm = kCCHmacAlgSHA1;
  39       algorithm_digest_length = CC_SHA1_DIGEST_LENGTH;
  40       break;
  41     default:
  42       NOTREACHED();
  43       return false;
  44   }
  45
  46   if (digest_length < algorithm_digest_length) {
  47     NOTREACHED();
  48     return false;
  49   }
  50
  51   CCHmac(algorithm,
  52          plat_->key_.data(), plat_->key_.length(), data.data(), data.length(),
  53          digest);
  54
  55   return true;
  56 }
  57
  58 }  // namespace base