public String decodeSamlAuthnRequest(final String encodedRequestXmlString) {
        if (StringUtils.isEmpty(encodedRequestXmlString)) {
            return null;
        }

        val decodedBytes = EncodingUtils.decodeBase64(encodedRequestXmlString);
        return inflateAuthnRequest(decodedBytes);
    }
Decode authn request xml.

@param encodedRequestXmlString the encoded request xml string
@return the request
support/cas-server-support-saml-core-api/src/main/java/org/apereo/cas/support/saml/util/AbstractSaml20ObjectBuilder.java