signal-desktop/protos/ContactDiscovery.proto

// Copyright 2021-2021 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only

package signalservice;

message CDSClientRequest {
  // Each ACI/UAK pair is a 32-byte buffer, containing the 16-byte ACI followed
  // by its 16-byte UAK.
  optional bytes aci_uak_pairs = 1;

  // Each E164 is an 8-byte big-endian number, as 8 bytes.
  optional bytes prev_e164s = 2;
  optional bytes new_e164s = 3;
  optional bytes discard_e164s = 4;

  // If true, the client has more pairs or e164s to send.  If false or unset,
  // this is the client's last request, and processing should commence.
  optional bool has_more = 5;

  // If set, a token which allows rate limiting to discount the e164s in
  // the request's prev_e164s, only counting new_e164s.  If not set, then
  // rate limiting considers both prev_e164s' and new_e164s' size.
  optional bytes token = 6;
}

message CDSClientResponse {
  // Each triple is an 8-byte e164, a 16-byte PNI, and a 16-byte ACI.
  // If the e164 was not found, PNI and ACI are all zeros.  If the PNI
  // was found but the ACI was not, the PNI will be non-zero and the ACI
  // will be all zeros.  ACI will be returned if one of the returned
  // PNIs has an ACI/UAK pair that matches.
  //
  // Should the request be successful (IE: a successful status returned),
  // |e164_pni_aci_triple| will always equal |e164| of the request,
  // so the entire marshalled size of the response will be (2+32)*|e164|,
  // where the additional 2 bytes are the id/type/length additions of the
  // protobuf marshaling added to each byte array.  This avoids any data
  // leakage based on the size of the encrypted output.
  optional bytes e164_pni_aci_triples = 1;

  // If the user has run out of quota for lookups, they will receive
  // a response with just the following field set, followed by a websocket
  // closure of type 4008 (RESOURCE_EXHAUSTED).  Should they retry exactly
  // the same request after the provided number of seconds has passed,
  // we expect it should work.
  optional int32 retry_after_secs = 2;

  // A token which allows subsequent calls' rate limiting to discount the
  // e164s sent up in this request, only counting those in the next
  // request's new_e164s.
  optional bytes token = 3;
}