components/sync/protocol/nigori_local_data.proto

// Copyright 2019 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.

// If you change or add any fields in this file, update proto_visitors.h and
// potentially proto_enum_conversions.{h, cc}.

syntax = "proto2";

option java_multiple_files = true;
option java_package = "org.chromium.components.sync.protocol";

option optimize_for = LITE_RUNTIME;

package sync_pb;

import "components/sync/protocol/encryption.proto";
import "components/sync/protocol/entity_metadata.proto";
import "components/sync/protocol/model_type_state.proto";
import "components/sync/protocol/nigori_specifics.proto";

message CryptographerData {
  // Contains all known Nigori keys.
  optional NigoriKeyBag key_bag = 1;

  // Default key is the key, that should be used for encryption. Can be empty
  // in case we have pending keys (waiting for explicit passphrase, or client
  // didn't received keystore keys).
  optional string default_key_name = 2;
}

message CustomPassphraseKeyDerivationParams {
  // Method used for deriving keys from custom passphrase.
  optional NigoriSpecifics.KeyDerivationMethod
      custom_passphrase_key_derivation_method = 1;

  // Salt used for the derivation of the key from the custom passphrase. Should
  // be set iff custom_passphrase_key_derivation_method == SCRYPT_8192_8_11.
  optional string custom_passphrase_key_derivation_salt = 2;
}

message NigoriModel {
  // Represents state of the cryptographer.
  optional CryptographerData cryptographer_data = 1;

  // Contains the name of the key, used for encryption of
  // NigoriSpecifics.keystore_decryptor_token, should always be the name of the
  // latest keystore key. Equals to cryptographer_data.default_key_name iff it
  // is Nigori in full keystore mode (not in backward compatible keystore
  // mode).
  optional string current_keystore_key_name = 2;

  // Contains keybag in encrypted form, should be empty once we were able to
  // decrypt keybag from specifics.
  optional EncryptedData pending_keys = 3;

  // PassphraseType used for encryption. IMPLICIT_PASSPRHASE shouldn't be used
  // here.
  optional NigoriSpecifics.PassphraseType passphrase_type = 4
      [default = UNKNOWN];

  // The time (in UNIX epoch milliseconds) at which the keystore migration was
  // performed.
  optional int64 keystore_migration_time = 5;

  // The time (in UNIX epoch milliseconds) at which a custom passphrase was
  // set.
  // Note: this field may not be set if the custom passphrase was applied before
  // corresponding field in NigoriSpecifics was introduced.
  optional int64 custom_passphrase_time = 6;

  // Params used for deriving keys from custom passphrase. Should be set iff
  // |passphrase_type| is CUSTOM_PASSPHRASE.
  optional CustomPassphraseKeyDerivationParams
      custom_passphrase_key_derivation_params = 7;

  // Indicates whether we need to encrypt all encryptable user types.
  optional bool encrypt_everything = 8;

  // The list of encrypted UserEncryptableTypes, represented by their specifics
  // field number.
  repeated int32 encrypted_types_specifics_field_number = 9;

  // Keystore keys are used to decrypt keystore-based Nigori. Should be
  // persisted in order to not ask the keystore server for them during every
  // browser startup. Due to backward compatibility requirements keys are
  // always Base64 encoded.
  repeated string keystore_key = 10;

  // Encryptor keystore decryptor token. Used for decryption of keystore Nigori
  // in case keystore keys arrived after NigoriSpecifics.
  optional EncryptedData pending_keystore_decryptor_token = 11;

  // Contains the name of the latest available trusted vault key that was used
  // as the default encryption key. Resets when the client go out of pending
  // decryption state and transits to other passphrase types.
  optional string last_default_trusted_vault_key_name = 12;

  // Some debug-only fields for passphrase type TRUSTED_VAULT_PASSPHRASE.
  optional NigoriSpecifics.TrustedVaultDebugInfo trusted_vault_debug_info = 13;
}

// Sync proto to store Nigori data in storage. Proto should be encrypted with
// os_crypt before storing it somewhere, because it contains sensitive data (
// nigori_model.cryptographer_data.key_bag and nigori_model.keystore_keys).
message NigoriLocalData {
  // Global metadata.
  optional ModelTypeState model_type_state = 1;

  // Metadata for Nigori entity.
  optional EntityMetadata entity_metadata = 2;

  // Nigori model state.
  optional NigoriModel nigori_model = 3;
}