[Cryptography] Chaum Has a Plan to End the Crypto War

[Christian Huitema]

On Thursday, January 7, 2016 8:31 AM, Jerry Leichter wrote:
> 
> > Call me crazy but there have been times past were I have wondered if
> > Chaum wasn't one of the worst things that has happened to cryptography.
> > Or at least the effective merger of cryptography and finance, which is
> > maybe the same thing.
> >
> > Now we have what amounts to the Chaumian "Star Chamber...."
> Actually, the problem is a bit broader than that.  The politicians will now be
> able to say "Look, you techies said this was impossible, but you were either
> just wrong or you lied.  It *is* possible.  Chaum showed you.  So now go off
> and build us the golden key."

>From the summary description of the proposal, it appears to use a "fragmented golden key." The classic golden key approach is to provide to authorities a copy of someone's private key, encrypted with the golden key. The fragmented approach appears to split the key in N fragments, each encrypted with the specific golden key of a different "council member," so that the N council members have to cooperate to recover the private key. It is not clear to me whether the design calls for unanimity or "M out of N," but both variations are obviously feasible.

Maybe I am just slow, but I don't see how in practice that fragmented golden key approach would be any more secure than the single golden key. It is certainly more complicated, which increases the probability of bugs and compromises. And it also provides a really big attack surface.

-- Christian Huitema