aes-js

A pure JavaScript implementation of the AES block cipher and all common modes of operation.

hashids

Generate YouTube-like ids from numbers. Use Hashids when you do not want to expose your database ids to the user.

md5-o-matic

Fast and simple MD5 hashing utility with zero module dependencies. View MD5 Shootout results, http://jsperf.com/md5-shootout/39