def _secure(self, args):
challenge = args.read_longstr()<EOL>
Security mechanism challenge

        The SASL protocol works by exchanging challenges and responses
        until both peers have received sufficient information to
        authenticate each other.  This method challenges the client to
        provide more information.

        PARAMETERS:
            challenge: longstr

                security challenge data

                Challenge information, a block of opaque binary data
                passed to the security mechanism.