vesta.proto

// Android copy of Vesta proto. Ground truth here:
//  - https://www.internalfb.com/code/fbsource/xplat/rust/vesta_client/proto/src/messages.proto
package whatsapp;
option java_package = "com.whatsapp.proto";

// Payload stored by successful registration (by `finish_register_request`).
message RegistrationPayload {
  // The secret data to be protected by the HSM system.
  // Holds serialized `WaBackupKeyData` proto.
  optional bytes backup_key_data = 1;
  // OPAQUE protocol third registration message.
  optional bytes r3 = 2;
  // Registration nonce.
  // Deprecated and soon to be removed. Replaced by `transcript` (see protocol spec).
  optional bytes opaque_challenge = 3;
  // History of registration messages: `SHA256(R1, R2, opaque_challenge)`
  optional bytes transcript = 4;
}

// Payload returned on successful account login (by `finish_login_request`).
message LoginPayload {
  // `backup_key_data` from `RegistrationPayload` AES-GCM-128 encrypted with
  // OPAQUE `shared_key`.
  optional bytes backup_key_data_encrypted = 1;
  // Nonce used for AES-GCM-128 encryption of `backup_key_data`.
  optional bytes rk_nonce = 2;
}

// WA-specific proto serialized to/from Vesta `backup_key_data` field.
message WaBackupKeyData {
  // User's backup key AES-GCM-128 encrypted with OPAQUE export key.
  optional bytes aes_k = 1;
  // Nonce used to AES-GCM-128 encrypt `aes_k`.
  optional bytes k_nonce = 2;
}