Example

 IMac mac = MacFactory.getInstance("HMAC-SHA-160");
 HashMap attributes = new HashMap();
 attributes.put(IMac.MAC_KEY_MATERIAL, key_bytes);
 attributes.put(IMac.TRUNCATED_SIZE, new Integer(12));
 mac.init(attributes);
 
 mac.update(input, 0, input.length);
 
 byte[] result = mac.digest();