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// Copyright 2012 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 <string>
#include "base/memory/scoped_ptr.h"
#include "sync/base/sync_export.h"
namespace crypto {
class SymmetricKey;
} // namespace crypto
namespace syncer {
// A (partial) implementation of Nigori, a protocol to securely store secrets in
// the cloud. This implementation does not support server authentication or
// assisted key derivation.
// To store secrets securely, use the |Permute| method to derive a lookup name
// for your secret (basically a map key), and |Encrypt| and |Decrypt| to store
// and retrieve the secret.
// TODO: Link to doc.
class SYNC_EXPORT Nigori {
enum Type {
Password = 1,
virtual ~Nigori();
// Initialize the client with the given |hostname|, |username| and |password|.
bool InitByDerivation(const std::string& hostname,
const std::string& username,
const std::string& password);
// Initialize the client by importing the given keys instead of deriving new
// ones.
bool InitByImport(const std::string& user_key,
const std::string& encryption_key,
const std::string& mac_key);
// Derives a secure lookup name from |type| and |name|. If |hostname|,
// |username| and |password| are kept constant, a given |type| and |name| pair
// always yields the same |permuted| value. Note that |permuted| will be
// Base64 encoded.
bool Permute(Type type, const std::string& name, std::string* permuted) const;
// Encrypts |value|. Note that on success, |encrypted| will be Base64
// encoded.
bool Encrypt(const std::string& value, std::string* encrypted) const;
// Decrypts |value| into |decrypted|. It is assumed that |value| is Base64
// encoded.
bool Decrypt(const std::string& value, std::string* decrypted) const;
// Exports the raw derived keys.
bool ExportKeys(std::string* user_key,
std::string* encryption_key,
std::string* mac_key) const;
static const char kSaltSalt[]; // The salt used to derive the user salt.
static const size_t kSaltKeySizeInBits = 128;
static const size_t kDerivedKeySizeInBits = 128;
static const size_t kIvSize = 16;
static const size_t kHashSize = 32;
static const size_t kSaltIterations = 1001;
static const size_t kUserIterations = 1002;
static const size_t kEncryptionIterations = 1003;
static const size_t kSigningIterations = 1004;
scoped_ptr<crypto::SymmetricKey> user_key_;
scoped_ptr<crypto::SymmetricKey> encryption_key_;
scoped_ptr<crypto::SymmetricKey> mac_key_;
} // namespace syncer