Re: Fwd: Re: [Cryptography] Encryption opinion

On 31/08/2014 12:59 AM, Karp, Alan H wrote:
> I don’t see that the ambient authority is an issue in this particular 
> case. Ihab’s blog may determine which page I see at Amazon, but Ihab 
> has no authority over that page even with ambient authority.

Ihab's blog has precisely the same authority over the Amazon page as the 
client of the compiler in the Confused Deputy scenario has over the 
billing path, ie. they can both designate a protected resource and 
confuse the agent with permission to write to that resource (the 
compiler, Amazon respsectively) into doing something undesirable.

In Ihab's blog, he just needs to create a page with a button that says 
"Animate Kittens", but which overlays the "buy now" Amazon button to 
trigger a $10,000 purchase. This is preventable in Waterken because the 
URLs are unique for all clients with a "buy now" button.

So how can a user be automatically redirected this unique URL from the 
public URL without also permitting malicious scripts from doing so?

Sandro