protected String getSigningAlgorithmFor(final Key signingKey) {
        return Optional.ofNullable(signingAlgorithm)
            .orElseGet(() -> "RSA".equalsIgnoreCase(signingKey.getAlgorithm())
                ? AlgorithmIdentifiers.RSA_USING_SHA512
                : AlgorithmIdentifiers.HMAC_SHA512);
    }
Gets signing algorithm for.

@param signingKey the signing key
@return the signing algorithm for
core/cas-server-core-util-api/src/main/java/org/apereo/cas/util/cipher/AbstractCipherExecutor.java