syntax = "proto3";
package passwordless_recovery;

// Recovery Process
// - Generating: TempID and a new assymetric key pair
// - Uploading to the server TempID + Push Tokens so the server can notify the user that someone helped him 


// Send from the person who tries to recover their account.
// This can be done via a link, which will then be opend in the app of the contact.
// The contact than has to manualy select from which user he got the request.
// -> Using this phishing is harder, as the user has to manualy select the user to recovery
// -> The user who wants to recover his account does not need to remember her old username
message RecoveryRequest {
  string notification_id = 1;
  bytes public_key = 2;
}

// Used as envelope for TrustedFriendShare and RecoveryData
message EncryptedEnvelope {
  bytes encrypted_data = 1;
  bytes iv = 2;
  bytes mac = 3;
}

// Send from the trusted friend to 
// This is encrypted with the received public key.
message TrustedFriendShare {

  // This allows to display the user which user has send him his recovery data.
  User trusted_friend = 1;

  // This allows to display the userdata, showing that he is recovering the correct person.
  User share_user = 2;

  // The minimum threshold required to decrypte the shares.
  int32 threshold = 3;

  // The actual share which will become: SharedSecretData
  bytes shared_secret_data = 4;

  message User {
    int64 user_id = 1;
    string display_name = 2;
    bytes avatar = 3;
  }
}

// The user identity keys. Can be used to restore the data backup.
message RecoveryData {
  int64 user_id = 1;
  bytes key_manager = 3;
}

// After received all shares this is decrypted by the user restoring its own 
message SharedSecretData {

  // The recovery data is encrypted in case a second factor was chosen.
  bytes recovery_data = 1;
  
  optional bytes encrypted_server_key_nonce = 3;

  optional bytes pin_seed = 4;
  optional bytes pin_unlock_token = 5;

  optional string email_hint = 6;

}