[teod]

I have thought about a similar service but was dissuaded by various sources warning against the idea of using javascript with cryptography, e.g. http://www.matasano.com/articles/javascript-cryptography/. That's not to say a reasonable solution cannot be found, but there are a good number of issues that need to be addressed. The one that seems crippling to me is that the strength of javascript crypto libraries is questionable at best - nevermind the various other javscript attack vectors. A browser plugin could address some issues, but then that limits users to browsers with the plugin installed. Might as well have a native application where the quality of the cryptographic algorithms are more thoroughly tested at that point. Still, I like the idea and wish you the best of luck.