End-To-End – Encrypy, Decrypt, Dogital Sign and Verify Signed Messages
https://code.google.com/p/end-to-end/

End-To-End is a Chrome extension that helps you encrypt, decrypt, digital sign, and verify signed messages within the browser using OpenPGP. This is the source code for the alpha release of the End-To-End Chrome extension. It’s built upon a newly developed, JavaScript-based crypto library. End-To-End implements the OpenPGP standard, IETF RFC 4880, enabling key generation, encryption, decryption, digital signature, and signature verification. We’re releasing this code to enable community review; it is not yet ready for general use. This will be added to Privacy Resources Subject Tracer™.