The last I heard from you on this topic in your previous thread:
http://forum.arduino.cc/index.php?topic=544041
you already had a library but hadn't figured out how to install it. I provided you installation instructions but never heard anything more on the subject.
So what's the point in people suggesting a library if you can't even install it. Don't you think it would be a good idea to first learn the basic and essential skill of installing a library before moving on to the advanced task of implementing an encryption algorithm?