@VisibleForTesting
    static String generateSignature(Credential signingCredential, String algorithmURI, String input) {
        try {
            final byte[] signature =
                    XMLSigningUtil.signWithURI(signingCredential, algorithmURI,
                                               input.getBytes(StandardCharsets.UTF_8));
            return Base64.getEncoder().encodeToString(signature);
        } catch (SecurityException e) {
            throw new SamlException("failed to generate a signature", e);
        }
    }
Generates a signature of the specified {@code input}.
saml/src/main/java/com/linecorp/armeria/server/saml/HttpRedirectBindingUtil.java