[JoachimSchipper]

Ah, I didn't expect a response. Nice.

I totally missed the part where you're willing to trust the server providing your Javascript (but not the storage node). That is a much more feasible design. Thanks for clarifying.

With respect to generating keys: PuTTY uses a blank rectangle and says "please randomly mouse over this". There's a simpler solution, though: since you're willing to trust a server, you can just let that generate a key for you.

Again, thanks for the clarification. You still have some chicken-and-egg problems to overcome, and you'll need to convince people to code in this way, but I'm happy to see that the basic design isn't as impossible as I'd feared.