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// Copyright (c) 2013 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 "net/quic/crypto/crypto_secret_boxer.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "crypto/secure_hash.h"
#include "crypto/sha2.h"
#include "net/quic/crypto/quic_random.h"
using base::StringPiece;
using std::string;
namespace net {
// Defined kKeySize for GetKeySize() and SetKey().
static const size_t kKeySize = 16;
// kBoxNonceSize contains the number of bytes of nonce that we use in each box.
static const size_t kBoxNonceSize = 16;
// static
size_t CryptoSecretBoxer::GetKeySize() { return kKeySize; }
void CryptoSecretBoxer::SetKey(StringPiece key) {
DCHECK_EQ(static_cast<size_t>(kKeySize), key.size());
key_ = key.as_string();
}
// TODO(rtenneti): Delete sha256 based code. Use Aes128Gcm12Encrypter to Box the
// plaintext. This is temporary solution for tests to pass.
string CryptoSecretBoxer::Box(QuicRandom* rand, StringPiece plaintext) const {
string ret;
const size_t len = kBoxNonceSize + plaintext.size() + crypto::kSHA256Length;
ret.resize(len);
char* data = &ret[0];
// Generate nonce.
rand->RandBytes(data, kBoxNonceSize);
memcpy(data + kBoxNonceSize, plaintext.data(), plaintext.size());
// Compute sha256 for nonce + plaintext.
scoped_ptr<crypto::SecureHash> sha256(crypto::SecureHash::Create(
crypto::SecureHash::SHA256));
sha256->Update(data, kBoxNonceSize + plaintext.size());
sha256->Finish(data + kBoxNonceSize + plaintext.size(),
crypto::kSHA256Length);
return ret;
}
// TODO(rtenneti): Delete sha256 based code. Use Aes128Gcm12Decrypter to Unbox
// the plaintext. This is temporary solution for tests to pass.
bool CryptoSecretBoxer::Unbox(StringPiece ciphertext,
string* out_storage,
StringPiece* out) const {
if (ciphertext.size() < kBoxNonceSize + crypto::kSHA256Length) {
return false;
}
const size_t plaintext_len =
ciphertext.size() - kBoxNonceSize - crypto::kSHA256Length;
out_storage->resize(plaintext_len);
char* data = const_cast<char*>(out_storage->data());
// Copy plaintext from ciphertext.
if (plaintext_len != 0) {
memcpy(data, ciphertext.data() + kBoxNonceSize, plaintext_len);
}
// Compute sha256 for nonce + plaintext.
scoped_ptr<crypto::SecureHash> sha256(crypto::SecureHash::Create(
crypto::SecureHash::SHA256));
sha256->Update(ciphertext.data(), ciphertext.size() - crypto::kSHA256Length);
char sha256_bytes[crypto::kSHA256Length];
sha256->Finish(sha256_bytes, sizeof(sha256_bytes));
// Verify sha256.
if (0 != memcmp(ciphertext.data() + ciphertext.size() - crypto::kSHA256Length,
sha256_bytes, crypto::kSHA256Length)) {
return false;
}
out->set(data, plaintext_len);
return true;
}
} // namespace net
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