[diafygi]

One aspect of in-browser functionality OP mentions is "offline". However, browsers are pretty cool in that they can mix offline and online. You can open a local html file and it can then make online requests. Alternatively, you can request an html file online that then can access local files.

This ability to mix offline and online content is something that I think has a lot of potential to improve client-side encryption. Specifically, client-side encryption coupled with an unhosted webapp[1].

I've been exploring this potential for my byoFS[2] project, and made an example end-to-end encrypted chat demo[3]. You can request the app anonymously (or even save it and open it locally). The app then lets the user connect an online datastore (e.g. Dropbox) to save the encrypted chats.

This separates who serves the anonymous static webapp and the authenticated datastore, and makes it much harder to target a javascript attack (the most common attack from the Snowden leaks).

[1] - https://unhosted.org/

[2] - https://github.com/diafygi/byoFS

[3] - https://diafygi.github.io/byoFS/examples/chat/