[Sync] Move //sync to //components/sync.

sync/util/nigori.h

-// 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.
-
-#ifndef SYNC_UTIL_NIGORI_H_
-#define SYNC_UTIL_NIGORI_H_
-
-#include <stddef.h>
-
-#include <memory>
-#include <string>
-
-#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.
-//
-// https://www.cl.cam.ac.uk/~drt24/nigori/nigori-overview.pdf
-class SYNC_EXPORT Nigori {
- public:
-  enum Type {
-    Password = 1,
-  };
-
-  Nigori();
-  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;
-
- private:
-  std::unique_ptr<crypto::SymmetricKey> user_key_;
-  std::unique_ptr<crypto::SymmetricKey> encryption_key_;
-  std::unique_ptr<crypto::SymmetricKey> mac_key_;
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_UTIL_NIGORI_H_