// Copyright 2016 The Fuchsia Authors
//
// 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 cobalt;

option go_package = "cobalt";

// An EncryptedMessage is used for several purposes in Cobalt. It carries
// the bytes of the ciphertext of the standard serialization of various
// types of proto messages.
message EncryptedMessage {
  // The different schemes used to encrypt a message.
  enum EncryptionScheme {
    // The message is not encrypted. |ciphertext| contains plaintext bytes
    // of a serialized protocol buffer message.
    // This scheme must only be used in tests.
    NONE = 0;

    // Hybrid Cipher using elliptic curve Diffie-Hellman, version 1.
    HYBRID_ECDH_V1 = 1;
  }

  // Which scheme was used to encrypt this message?
  EncryptionScheme scheme = 1;

  // 32-byte fingerprint (SHA256) of the recipient’s public key.
  // This is used to facilitate key rotation.
  bytes public_key_fingerprint = 2;

  bytes ciphertext = 3; // The encryption of the standard serialization of some
                        // proto message. Which message is determined by
                        // context.
}