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