Verify the received OIDC 'nonce' from the ID Token.
        :param nonce: OIDC nonce
        :type nonce: str
        :param context: current request context
        :type context: satosa.context.Context
        :raise SATOSAAuthenticationError: if the nonce is incorrect

def _verify_nonce(self, nonce, context):
        """
        Verify the received OIDC 'nonce' from the ID Token.
        :param nonce: OIDC nonce
        :type nonce: str
        :param context: current request context
        :type context: satosa.context.Context
        :raise SATOSAAuthenticationError: if the nonce is incorrect
        """
        backend_state = context.state[self.name]
        if nonce != backend_state[NONCE_KEY]:
            satosa_logging(logger, logging.DEBUG,
                           "Missing or invalid nonce in authn response for state: %s" %
                           backend_state,
                           context.state)
            raise SATOSAAuthenticationError(context.state, "Missing or invalid nonce in authn response")