protected void prepareSecurityParametersContext(
        final SamlRegisteredServiceMetadataAdaptor adaptor,
        final MessageContext outboundContext,
        final SamlRegisteredService service) {
        val secParametersContext = outboundContext.ensureSubcontext(SecurityParametersContext.class);
        val roleDesc = adaptor.getSsoDescriptor();
        val signingParameters = buildSignatureSigningParameters(roleDesc, service);
        Objects.requireNonNull(secParametersContext).setSignatureSigningParameters(signingParameters);
    }
Prepare security parameters context.

@param adaptor         the adaptor
@param outboundContext the outbound context
@param service         the service
support/cas-server-support-saml-idp-web/src/main/java/org/apereo/cas/support/saml/web/idp/profile/builders/enc/DefaultSamlIdPObjectSigner.java