private static Boolean isAuthnRequestSigned(final SamlRegisteredService registeredService, final HttpServletRequest request,
                                                final AuthnRequest authnRequest, final MessageContext messageContext,
                                                final SamlProfileHandlerConfigurationContext context) {
        val isSigned = authnRequest.isSigned() || SAMLBindingSupport.isMessageSigned(messageContext);
        if (isSigned) {
            val entityId = SamlIdPUtils.getIssuerFromSamlObject(authnRequest);
            val adaptor = SamlRegisteredServiceMetadataAdaptor.get(context.getSamlRegisteredServiceCachingMetadataResolver(), registeredService, entityId).orElseThrow();
            return FunctionUtils.doAndHandle(() -> context.getSamlObjectSignatureValidator()
                .verifySamlProfileRequest(authnRequest, adaptor, request, messageContext));
        }
        return false;
    }
This is {@link SamlIdPMultifactorAuthenticationTrigger}.

@author Misagh Moayyed
@since 6.4.0
support/cas-server-support-saml-idp-web/src/main/java/org/apereo/cas/support/saml/web/idp/web/SamlIdPMultifactorAuthenticationTrigger.java