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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "crypto/encryptor.h"
#include <CommonCrypto/CommonCryptor.h>
#include "base/logging.h"
#include "base/string_util.h"
#include "crypto/symmetric_key.h"
namespace crypto {
Encryptor::Encryptor()
: key_(NULL),
mode_(CBC) {
}
Encryptor::~Encryptor() {
}
bool Encryptor::Init(SymmetricKey* key,
Mode mode,
const base::StringPiece& iv) {
DCHECK(key);
DCHECK_EQ(CBC, mode) << "Unsupported mode of operation";
CSSM_DATA raw_key = key->cssm_data();
if (raw_key.Length != kCCKeySizeAES128 &&
raw_key.Length != kCCKeySizeAES192 &&
raw_key.Length != kCCKeySizeAES256)
return false;
if (iv.size() != kCCBlockSizeAES128)
return false;
key_ = key;
mode_ = mode;
iv.CopyToString(&iv_);
return true;
}
bool Encryptor::Crypt(int /*CCOperation*/ op,
const base::StringPiece& input,
std::string* output) {
DCHECK(key_);
CSSM_DATA raw_key = key_->cssm_data();
// CommonCryptor.h: "A general rule for the size of the output buffer which
// must be provided by the caller is that for block ciphers, the output
// length is never larger than the input length plus the block size."
size_t output_size = input.size() + iv_.size();
CHECK_GT(output_size, 0u);
CHECK_GT(output_size + 1, input.size());
CCCryptorStatus err = CCCrypt(op,
kCCAlgorithmAES128,
kCCOptionPKCS7Padding,
raw_key.Data, raw_key.Length,
iv_.data(),
input.data(), input.size(),
WriteInto(output, output_size + 1),
output_size,
&output_size);
if (err) {
output->clear();
LOG(ERROR) << "CCCrypt returned " << err;
return false;
}
output->resize(output_size);
return true;
}
bool Encryptor::Encrypt(const base::StringPiece& plaintext,
std::string* ciphertext) {
CHECK(!plaintext.empty() || (mode_ == CBC));
return Crypt(kCCEncrypt, plaintext, ciphertext);
}
bool Encryptor::Decrypt(const base::StringPiece& ciphertext,
std::string* plaintext) {
CHECK(!ciphertext.empty());
return Crypt(kCCDecrypt, ciphertext, plaintext);
}
} // namespace crypto
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