}
        return hash;
    }

    public String encodeSimilarDocHash(final String hash) {
        if (hash != null && !hash.startsWith(SIMILAR_DOC_HASH_PREFIX)) {
            try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
                try (GZIPOutputStream gos = new GZIPOutputStream(baos)) {
                    gos.write(hash.getBytes(Constants.UTF_8));
                }