protected String uncompressLogoutMessage(final String originalMessage) {
        val binaryMessage = Base64.getMimeDecoder().decode(originalMessage);

        Inflater decompresser = null;
        try {
            // decompress the bytes
            decompresser = new Inflater();
            decompresser.setInput(binaryMessage);
            val result = new byte[binaryMessage.length * DECOMPRESSION_FACTOR];

            val resultLength = decompresser.inflate(result);

            // decode the bytes into a String
            return new String(result, 0, resultLength, "UTF-8");
        } catch (final Exception e) {
            LOGGER.error("Unable to decompress logout message", e);
            throw new TechnicalException(e);
        } finally {
            if (decompresser != null) {
                decompresser.end();
            }
        }
    }
<p>uncompressLogoutMessage.</p>

@param originalMessage a {@link String} object
@return a {@link String} object
pac4j-cas/src/main/java/org/pac4j/cas/credentials/extractor/CasCredentialsExtractor.java