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