private String getPasswordDigest(String nonce, String timestamp) {
        try {
            MessageDigest messageDigest = MessageDigest.getInstance("SHA-1");
            messageDigest.reset();
            String hashedString = String.format("%s%s%s", nonce, timestamp, apiSecretKey);
            messageDigest.update(hashedString.getBytes(StandardCharsets.UTF_8));
            String sha1Sum = bytesToHex(messageDigest.digest());

            return DatatypeConverter.printBase64Binary(sha1Sum.getBytes(StandardCharsets.UTF_8));
        } catch (NoSuchAlgorithmException ex) {
            throw new RuntimeException(ex);
        }
    }