mautrix-signal/pkg/signalmeow/protobuf/org/signal/chat/challenge.proto

/*
 * Copyright 2026 Signal Messenger, LLC
 * SPDX-License-Identifier: AGPL-3.0-only
 */

syntax = "proto3";

option java_multiple_files = true;

package org.signal.chat.challenge;

import "org/signal/chat/require.proto";

service Challenge {
  option (require.auth) = AUTH_ONLY_AUTHENTICATED;
  // Submit proof of a challenge completion

  //  Some server endpoints (the "send message" endpoint, for example) may return
  //  a response indicating the client must complete a challenge before continuing.
  //  Clients may use this endpoint to provide proof of a completed challenge.
  //  If successful, the client may then continue their original operation.
  rpc HandleChallengeResponse(AnswerChallengeRequest) returns (AnswerChallengeResponse) {}
}

message AnswerChallengeRequest {

  message AnswerPushChallengeRequest {
    // The challenge string provided to the client via a push payload
    string challenge = 1  [(require.nonEmpty) = true];
  }

  message AnswerCaptchaChallengeRequest {
    // A string representing a solved captcha
    // Example: signal-hcaptcha.30b01b46-d8c9-4c30-bbd7-9719acfe0c10.challenge.abcdefg1345
    string captcha = 1  [(require.nonEmpty) = true];
  }

  // The opaque token id from the ChallengeRequired response returned by the
  // server endpoint that requested the challenge
  string token = 1  [(require.nonEmpty) = true];

  oneof request {
    AnswerPushChallengeRequest push = 2;
    AnswerCaptchaChallengeRequest captcha = 3;
  }

}

message AnswerChallengeResponse {
  // Whether the challenge proof was accepted
  bool success = 1;
}