SOLDIERX.COM Nobody Can Stop Information Insemination

This is pretty good:
https://cryptup.org/

Source code isn't linked on the page, but it's here:
https://github.com/tomholub/cryptup-chrome

Points of interest
- Uses OpenPGP.js under the hood
- Stores keys in browser's local / session storage. This means if your machine or browser is compromised, so are your keys.