SPIKE Password protect message

Determine what mechanism, if any, could be used to send and view password protected messages.
Questions to answer
- What method to use. Maybe [cryptojs w/ AES](https://code.google.com/p/crypto-js/#AES) with a PBKDF2 key?
- How to read messages:
  - Query strings can be ~2000 chars. Maybe we send recipient a link to our app with message in it?
  - Store messages w/ API server in Mongo?
