libs/connecteddevice/src/com/google/android/connecteddevice/trust/proto/trusted_device_message.proto

/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

syntax = "proto3";

package com.google.android.connecteddevice.trust.proto;

option java_package = "com.google.android.connecteddevice.trust.proto";
option java_outer_classname = "TrustedDeviceMessageProto";

// A message specific to the trusted device feature.
message TrustedDeviceMessage {
  // The current version of this proto. Must be positive but declared as an
  // int32 for interoperability reasons.
  int32 version = 1;

  // The different message types that indicate the content of the payload.
  enum MessageType {
    // The contents of the payload are unknown.
    MESSAGE_TYPE_UNKNOWN = 0;

    // This message is a request for the other device to start the enrollment
    // process. The payload is empty for this type.
    START_ENROLLMENT = 1;

    // This message payload contains the escrow token.
    ESCROW_TOKEN = 2;

    // This message payload contains the unlock handle.
    HANDLE = 3;

    // The payload of this message contains all the necessary information to
    // unlock the other device.
    UNLOCK_CREDENTIALS = 4;

    // An acknowledgment for a previous message. The payload will be empty
    // for this type.
    ACK = 5;

    // An error has occurred on the sender of this message. The payload will be
    // a message of TrustedDeviceError. Both sender and receiver should reset
    // their states after this message.
    ERROR = 6;
  }

  // The type of this message.
  MessageType type = 2;

  // The bytes that represent the content for this message.
  bytes payload = 3;
}

// An error message. Should only be sent as `TrustedDeviceMessage.payload` when
// `type` is `MessageType.ERROR`.
message TrustedDeviceError {
  enum ErrorType {
    // The contents of the payload are unknown.
    MESSAGE_TYPE_UNKNOWN = 0;

    // This device does not meet the requirement of device security to start
    // enrollment. Instead of escrow token, send this error.
    DEVICE_NOT_SECURED = 1;
  }

  // The type of this error.
  ErrorType type = 1;
}