mac.init(keySpec);
byte[] result = mac.doFinal(message.getBytes(Charset.forName("UTF-8")));
String encodedResult = Hex.encodeHexString(result);
return encodedResult;
} catch (NoSuchAlgorithmException e) {
throw new InstagramException("Invalid algorithm name!", e);
} catch (InvalidKeyException e) {
throw new InstagramException("Invalid key: " + clientSecret, e);
}
}