protected byte[] sign(final byte[] value, final Key signingKey) {
        if (signingKey == null) {
            return value;
        }
        return signWith(value, getSigningAlgorithmFor(signingKey));
    }
Sign the array by first turning it into a base64 encoded string.

@param value      the value
@param signingKey the signing key
@return the byte [ ]
core/cas-server-core-util-api/src/main/java/org/apereo/cas/util/cipher/AbstractCipherExecutor.java