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
Encryptor()15 Encryptor::Encryptor()
16 : key_(NULL),
17 mode_(CBC) {
18 }
19
~Encryptor()20 Encryptor::~Encryptor() {
21 }
22
Init(SymmetricKey * key,Mode mode,const std::string & iv)23 bool 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
Crypt(int op,const std::string & input,std::string * output)40 bool 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
Encrypt(const std::string & plaintext,std::string * ciphertext)68 bool Encryptor::Encrypt(const std::string& plaintext, std::string* ciphertext) {
69 return Crypt(kCCEncrypt, plaintext, ciphertext);
70 }
71
Decrypt(const std::string & ciphertext,std::string * plaintext)72 bool Encryptor::Decrypt(const std::string& ciphertext, std::string* plaintext) {
73 return Crypt(kCCDecrypt, ciphertext, plaintext);
74 }
75
76 } // namespace crypto
77