private static String getRegisteredServiceJwtProperty(final RegisteredService registeredService,
                                                          final RegisteredServiceProperties propName) {
        if (registeredService == null || !registeredService.getAccessStrategy().isServiceAccessAllowed(registeredService, null)) {
            LOGGER.debug("Service is not defined/found or its access is disabled in the registry");
            throw UnauthorizedServiceException.denied("Denied");
        }
        if (propName.isAssignedTo(registeredService)) {
            val propertyValue = propName.getPropertyValue(registeredService).value();
            return SpringExpressionLanguageValueResolver.getInstance().resolve(propertyValue);
        }
        LOGGER.trace("Service [{}] does not define a property [{}] in the registry", registeredService.getServiceId(), propName);
        return null;
    }
Create a JWT authenticator.

@return the jwt authenticator
support/cas-server-support-token-authentication/src/main/java/org/apereo/cas/token/authentication/TokenAuthenticationSecurity.java