protected String getSignatureAlgorithmURI(final SignatureSigningParameters signingParameters)
        throws MessageEncodingException {

        if (signingParameters.getSignatureAlgorithm() != null) {
            return signingParameters.getSignatureAlgorithm();
        }

        throw new MessageEncodingException("The signing algorithm URI could not be determined");
    }
Gets the signature algorithm URI to use.

@param signingParameters the signing parameters to use
@return signature algorithm to use with the associated signing credential
@throws MessageEncodingException thrown if the algorithm URI is not supplied explicitly and
                                 could not be derived from the supplied credential
pac4j-saml/src/main/java/org/pac4j/saml/transport/Pac4jHTTPRedirectDeflateEncoder.java