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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/time/time.h"
#include "sync/base/sync_export.h"
#include "sync/internal_api/public/base/model_type.h"
namespace sync_pb {
class EncryptedData;
namespace syncer {
class Cryptographer;
// Reasons due to which Cryptographer might require a passphrase.
enum PassphraseRequiredReason {
REASON_ENCRYPTION = 1, // The cryptographer requires a
// passphrase for its first attempt at
// encryption. Happens only during
// migration or upgrade.
REASON_DECRYPTION = 2, // The cryptographer requires a
// passphrase for its first attempt at
// decryption.
// The different states for the encryption passphrase. These control if and how
// the user should be prompted for a decryption passphrase.
enum PassphraseType {
IMPLICIT_PASSPHRASE = 0, // GAIA-based passphrase (deprecated).
KEYSTORE_PASSPHRASE = 1, // Keystore passphrase.
FROZEN_IMPLICIT_PASSPHRASE = 2, // Frozen GAIA passphrase.
CUSTOM_PASSPHRASE = 3, // User-provided passphrase.
// Enum used to distinguish which bootstrap encryption token is being updated.
enum BootstrapTokenType {
// Sync's encryption handler. Handles tracking encrypted types, ensuring the
// cryptographer encrypts with the proper key and has the most recent keybag,
// and keeps the nigori node up to date.
// Implementations of this class must be assumed to be non-thread-safe. All
// methods must be invoked on the sync thread.
class SYNC_EXPORT SyncEncryptionHandler {
// All Observer methods are done synchronously from within a transaction and
// on the sync thread.
class SYNC_EXPORT Observer {
// Called when user interaction is required to obtain a valid passphrase.
// - If the passphrase is required for encryption, |reason| will be
// - If the passphrase is required for the decryption of data that has
// already been encrypted, |reason| will be REASON_DECRYPTION.
// - If the passphrase is required because decryption failed, and a new
// passphrase is required, |reason| will be REASON_SET_PASSPHRASE_FAILED.
// |pending_keys| is a copy of the cryptographer's pending keys, that may be
// cached by the frontend for subsequent use by the UI.
virtual void OnPassphraseRequired(
PassphraseRequiredReason reason,
const sync_pb::EncryptedData& pending_keys) = 0;
// Called when the passphrase provided by the user has been accepted and is
// now used to encrypt sync data.
virtual void OnPassphraseAccepted() = 0;
// |bootstrap_token| is an opaque base64 encoded representation of the key
// generated by the current passphrase, and is provided to the observer for
// persistence purposes and use in a future initialization of sync (e.g.
// after restart). The boostrap token will always be derived from the most
// recent GAIA password (for accounts with implicit passphrases), even if
// the data is still encrypted with an older GAIA password. For accounts
// with explicit passphrases, it will be the most recently seen custom
// passphrase.
virtual void OnBootstrapTokenUpdated(
const std::string& bootstrap_token,
BootstrapTokenType type) = 0;
// Called when the set of encrypted types or the encrypt
// everything flag has been changed. Note that encryption isn't
// complete until the OnEncryptionComplete() notification has been
// sent (see below).
// |encrypted_types| will always be a superset of
// Cryptographer::SensitiveTypes(). If |encrypt_everything| is
// true, |encrypted_types| will be the set of all known types.
// Until this function is called, observers can assume that the
// set of encrypted types is Cryptographer::SensitiveTypes() and
// that the encrypt everything flag is false.
virtual void OnEncryptedTypesChanged(
ModelTypeSet encrypted_types,
bool encrypt_everything) = 0;
// Called after we finish encrypting the current set of encrypted
// types.
virtual void OnEncryptionComplete() = 0;
// The cryptographer has been updated. Listeners should check that their
// own state matches the cryptographer.
// Used primarily for debugging.
virtual void OnCryptographerStateChanged(Cryptographer* cryptographer) = 0;
// The passphrase type has changed. |type| is the new type,
// |passphrase_time| is the time the passphrase was set (unset if |type|
// is KEYSTORE_PASSPHRASE or the passphrase was set before we started
// recording the time).
virtual void OnPassphraseTypeChanged(PassphraseType type,
base::Time passphrase_time) = 0;
virtual ~Observer();
virtual ~SyncEncryptionHandler();
// Add/Remove SyncEncryptionHandler::Observers.
virtual void AddObserver(Observer* observer) = 0;
virtual void RemoveObserver(Observer* observer) = 0;
// Reads the nigori node, updates internal state as needed, and, if an
// empty/stale nigori node is detected, overwrites the existing
// nigori node. Upon completion, if the cryptographer is still ready
// attempts to re-encrypt all sync data.
// Note: This method is expensive (it iterates through all encrypted types),
// so should only be used sparingly (e.g. on startup).
virtual void Init() = 0;
// Attempts to re-encrypt encrypted data types using the passphrase provided.
// Notifies observers of the result of the operation via OnPassphraseAccepted
// or OnPassphraseRequired, updates the nigori node, and does re-encryption as
// appropriate. If an explicit password has been set previously, we drop
// subsequent requests to set a passphrase. If the cryptographer has pending
// keys, and a new implicit passphrase is provided, we try decrypting the
// pending keys with it, and if that fails, we cache the passphrase for
// re-encryption once the pending keys are decrypted.
virtual void SetEncryptionPassphrase(const std::string& passphrase,
bool is_explicit) = 0;
// Provides a passphrase for decrypting the user's existing sync data.
// Notifies observers of the result of the operation via OnPassphraseAccepted
// or OnPassphraseRequired, updates the nigori node, and does re-encryption as
// appropriate if there is a previously cached encryption passphrase. It is an
// error to call this when we don't have pending keys.
virtual void SetDecryptionPassphrase(const std::string& passphrase) = 0;
// Enables encryption of all datatypes.
virtual void EnableEncryptEverything() = 0;
// Whether encryption of all datatypes is enabled. If false, only sensitive
// types are encrypted.
virtual bool EncryptEverythingEnabled() const = 0;
// Returns the current state of the passphrase needed to decrypt the
// bag of encryption keys in the nigori node.
virtual PassphraseType GetPassphraseType() const = 0;
// The set of types that are always encrypted.
static ModelTypeSet SensitiveTypes();
} // namespace syncer