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// Copyright 2015 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 "components/gcm_driver/crypto/gcm_crypto_test_helpers.h"
#include <stddef.h>
#include <sstream>
#include <string>
#include "base/base64url.h"
#include "base/strings/string_util.h"
#include "components/gcm_driver/common/gcm_message.h"
#include "components/gcm_driver/crypto/gcm_message_cryptographer.h"
#include "components/gcm_driver/crypto/p256_key_util.h"
#include "crypto/ec_private_key.h"
#include "crypto/random.h"
namespace gcm {
bool CreateEncryptedPayloadForTesting(const base::StringPiece& payload,
const base::StringPiece& peer_public_key,
const base::StringPiece& auth_secret,
IncomingMessage* message) {
DCHECK(message);
// Create an ephemeral key for the sender.
std::unique_ptr<crypto::ECPrivateKey> key = crypto::ECPrivateKey::Create();
if (!key)
return false;
std::string shared_secret;
// Calculate the shared secret between the sender and its peer.
if (!ComputeSharedP256Secret(*key, peer_public_key, &shared_secret)) {
return false;
}
std::string salt;
// Generate a cryptographically secure random salt for the message.
const size_t salt_size = GCMMessageCryptographer::kSaltSize;
crypto::RandBytes(base::WriteInto(&salt, salt_size + 1), salt_size);
GCMMessageCryptographer cryptographer(
GCMMessageCryptographer::Version::DRAFT_03);
size_t record_size;
std::string ciphertext;
std::string public_key;
if (!GetRawPublicKey(*key, &public_key))
return false;
if (!cryptographer.Encrypt(peer_public_key, public_key, shared_secret,
auth_secret, salt, payload, &record_size,
&ciphertext)) {
return false;
}
std::string encoded_salt, encoded_public_key;
// Create base64url encoded representations of the salt and local public key.
base::Base64UrlEncode(salt, base::Base64UrlEncodePolicy::OMIT_PADDING,
&encoded_salt);
base::Base64UrlEncode(public_key, base::Base64UrlEncodePolicy::OMIT_PADDING,
&encoded_public_key);
// Write the Encryption header value to |*message|.
std::stringstream encryption_header;
encryption_header << "salt=" << encoded_salt << ";rs=" << record_size;
message->data["encryption"] = encryption_header.str();
// Write the Crypto-Key value to |*message|.
std::stringstream crypto_key_header;
crypto_key_header << "dh=" << encoded_public_key;
message->data["crypto-key"] = crypto_key_header.str();
message->raw_data.swap(ciphertext);
return true;
}
} // namespace gcm
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