crypto/encryptor_mac.cc

   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/encryptor.h"
   6
   7 #include <CommonCrypto/CommonCryptor.h>
   8
   9 #include "base/logging.h"
  10 #include "base/string_util.h"
  11 #include "crypto/symmetric_key.h"
  12
  13 namespace crypto {
  14
  15 Encryptor::Encryptor()
  16     : key_(NULL),
  17       mode_(CBC) {
  18 }
  19
  20 Encryptor::~Encryptor() {
  21 }
  22
  23 bool Encryptor::Init(SymmetricKey* key,
  24                      Mode mode,
  25                      const base::StringPiece& iv) {
  26   DCHECK(key);
  27   DCHECK_EQ(CBC, mode) << "Unsupported mode of operation";
  28   CSSM_DATA raw_key = key->cssm_data();
  29   if (raw_key.Length != kCCKeySizeAES128 &&
  30       raw_key.Length != kCCKeySizeAES192 &&
  31       raw_key.Length != kCCKeySizeAES256)
  32     return false;
  33   if (iv.size() != kCCBlockSizeAES128)
  34     return false;
  35
  36   key_ = key;
  37   mode_ = mode;
  38   iv.CopyToString(&iv_);
  39   return true;
  40 }
  41
  42 bool Encryptor::Crypt(int /*CCOperation*/ op,
  43                       const base::StringPiece& input,
  44                       std::string* output) {
  45   DCHECK(key_);
  46   CSSM_DATA raw_key = key_->cssm_data();
  47   // CommonCryptor.h: "A general rule for the size of the output buffer which
  48   // must be provided by the caller is that for block ciphers, the output
  49   // length is never larger than the input length plus the block size."
  50
  51   size_t output_size = input.size() + iv_.size();
  52   CCCryptorStatus err = CCCrypt(op,
  53                                 kCCAlgorithmAES128,
  54                                 kCCOptionPKCS7Padding,
  55                                 raw_key.Data, raw_key.Length,
  56                                 iv_.data(),
  57                                 input.data(), input.size(),
  58                                 WriteInto(output, output_size+1),
  59                                 output_size,
  60                                 &output_size);
  61   if (err) {
  62     output->resize(0);
  63     LOG(ERROR) << "CCCrypt returned " << err;
  64     return false;
  65   }
  66   output->resize(output_size);
  67   return true;
  68 }
  69
  70 bool Encryptor::Encrypt(const base::StringPiece& plaintext,
  71                         std::string* ciphertext) {
  72   return Crypt(kCCEncrypt, plaintext, ciphertext);
  73 }
  74
  75 bool Encryptor::Decrypt(const base::StringPiece& ciphertext,
  76                         std::string* plaintext) {
  77   return Crypt(kCCDecrypt, ciphertext, plaintext);
  78 }
  79
  80 }  // namespace crypto