A worse and impossible to mitigate problem in other scenarios is that user agents will cheerfully "bookmark" or "favourite" a URL or just let you "share" it and it's often not obvious to the end user that this shares their current state which they probably don't want not just the thing they're looking at. Example: you try to share the forum help link but instead give the recipient your logged in account...

This is the reason not to put authentication tokens into URLs for example.

When the state users want to bookmark or share literally is the state that's encrypted anyway this mismatch isn't a threat. If I send you the URL for this drawing of a cat and then I'm astonished you can now see the drawing of the cat I've got real problems technology can't fix.

yeah, this.

Having the key in the url seems insanely insecure to me.

Why? It makes it easy to share a sketch with someone else while still preventing the server from decrypting the data. Anything stored in a location hash (after the # symbol) does not get passed to the server.

The threat model the author tried to work around is not the user dumbly compromising their own work. The author wants to prevent proprietary and PII data from being stored on their own server. End-to-end encryption significantly reduces the author's potential liability hosting something like this in case something goes wrong.

> Why? It makes it easy to share a sketch with someone else while still preventing the server from decrypting the data. Anything stored in a location hash (after the # symbol) does not get passed to the server.

I'll hit the URL bar and hit control-C. That's way better than any javashit which wants to touch my clipboard.

Copying the current URL also copies the key in that case. Now I'm accidentally sharing my encryption information with another user.

That's literally the use-case of pasting the link to your sketch to someone. The app itself is not touching your clipboard. Take a careful look at how this works, it's perfectly innocuous.