/// <summary>
        /// Utility method to signs the UserSignatureEventArgs server nonce from
        /// a private credentials file.
        /// </summary>
        /// <param name="credsFile">A file with the private Nkey</param>
        /// <param name="args">Arguments</param>
        public static void SignNonceFromFile(string credsFile, UserSignatureEventArgs args)
        {
            var kp = LoadNkeyPairFromSeedFile(credsFile);

            args.SignedNonce = kp.Sign(args.ServerNonce);
            kp.Wipe();
        }
 /// <summary>
 /// The default User Signature event handler.
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="args"></param>
 public void DefaultUserSignatureHandler(object sender, UserSignatureEventArgs args)
 {
     SignNonceFromFile(credsFile, args);
 }