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// Copyright (c) 2010 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 "base/crypto/symmetric_key.h"
#include <openssl/evp.h>
#include <openssl/rand.h>
#include <algorithm>
#include "base/logging.h"
#include "base/openssl_util.h"
#include "base/scoped_ptr.h"
#include "base/string_util.h"
namespace base {
SymmetricKey::~SymmetricKey() {
std::fill(key_.begin(), key_.end(), '\0'); // Zero out the confidential key.
}
// static
SymmetricKey* SymmetricKey::GenerateRandomKey(Algorithm algorithm,
size_t key_size_in_bits) {
DCHECK_EQ(AES, algorithm);
int key_size_in_bytes = key_size_in_bits / 8;
DCHECK_EQ(static_cast<int>(key_size_in_bits), key_size_in_bytes * 8);
if (key_size_in_bits == 0)
return NULL;
scoped_ptr<SymmetricKey> key(new SymmetricKey);
uint8* key_data =
reinterpret_cast<uint8*>(WriteInto(&key->key_, key_size_in_bytes + 1));
int res = RAND_bytes(key_data, key_size_in_bytes);
if (res != 1) {
DLOG(ERROR) << "RAND_bytes failed. res = " << res;
ClearOpenSSLERRStack();
return NULL;
}
return key.release();
}
// static
SymmetricKey* SymmetricKey::DeriveKeyFromPassword(Algorithm algorithm,
const std::string& password,
const std::string& salt,
size_t iterations,
size_t key_size_in_bits) {
DCHECK(algorithm == AES || algorithm == HMAC_SHA1);
int key_size_in_bytes = key_size_in_bits / 8;
DCHECK_EQ(static_cast<int>(key_size_in_bits), key_size_in_bytes * 8);
scoped_ptr<SymmetricKey> key(new SymmetricKey);
uint8* key_data =
reinterpret_cast<uint8*>(WriteInto(&key->key_, key_size_in_bytes + 1));
int res = PKCS5_PBKDF2_HMAC_SHA1(password.data(), password.length(),
reinterpret_cast<const uint8*>(salt.data()),
salt.length(), iterations,
key_size_in_bytes, key_data);
if (res != 1) {
DLOG(ERROR) << "HMAC SHA1 failed. res = " << res;
ClearOpenSSLERRStack();
return NULL;
}
return key.release();
}
// static
SymmetricKey* SymmetricKey::Import(Algorithm algorithm,
const std::string& raw_key) {
scoped_ptr<SymmetricKey> key(new SymmetricKey);
key->key_ = raw_key;
return key.release();
}
bool SymmetricKey::GetRawKey(std::string* raw_key) {
*raw_key = key_;
return true;
}
} // namespace base
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