SessionRecord.proto

//
// Copyright 2020 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//

syntax = "proto2";

// iOS - package name determines class prefix
package SessionRecordProtos;

message SessionStructure {
  message Chain {
    optional bytes senderRatchetKey = 1;
    optional bytes senderRatchetKeyPrivate = 2;

    message ChainKey {
      optional uint32 index = 1;
      optional bytes key = 2;
    }

    optional ChainKey chainKey = 3;

    message MessageKey {
      optional uint32 index = 1;
      optional bytes cipherKey = 2;
      optional bytes macKey = 3;
      optional bytes iv = 4;
    }

    repeated MessageKey messageKeys = 4;
  }

  message PendingPreKey {
    optional uint32 preKeyId = 1;
    optional int32 signedPreKeyId = 3;
    optional bytes baseKey = 2;
  }

  optional uint32 sessionVersion = 1;
  optional bytes localIdentityPublic = 2;
  optional bytes remoteIdentityPublic = 3;

  optional bytes rootKey = 4;
  optional uint32 previousCounter = 5;

  optional Chain senderChain = 6;
  // The order is significant; keys at the end are "older" and will get trimmed.
  repeated Chain receiverChains = 7;

  optional PendingPreKey pendingPreKey = 9;

  optional uint32 remoteRegistrationId = 10;
  optional uint32 localRegistrationId = 11;

  optional bool needsRefresh = 12;
  optional bytes aliceBaseKey = 13;
}

message RecordStructure {
  optional SessionStructure currentSession = 1;
  // The order is significant; sessions at the end are "older" and will get trimmed.
  repeated SessionStructure previousSessions = 2;
}