[cryptography] NIST Randomness Beacon

Warren Kumari warren at kumari.net
Mon Nov 11 18:56:47 EST 2013

On Nov 11, 2013, at 6:28 PM, Peter Gutmann <pgut001 at cs.auckland.ac.nz> wrote:

> Warren Kumari <warren at kumari.net> writes:
>> I've often wondered if there is a clever way to do the inverse -- basically
>> to have a "latest" timestamp? This seems like a much harder problem -- 'm
>> looking for a "movie plot" type solution that the public can easily
>> understand…
> You could do it with a physical one-way function.  Take a photo of the victim
> on top of the WTC and you know that it can't have been occurred after 9/11. To
> generalise it, photograph the victim in front of some documented object and
> then destroy the object.

Ok, cute, thank you -- still suffers from the "I take a photo of the object, then blow it up. Three weeks later I print out the photo and take a photo of the victim in front of it" attack, but I like the idea...

>  I'm assuming in the movie-plot scenario that someone
> who's kidnapped a victim won't worry about blowing up a statue in a park or
> performing whatever the physical one-way operation is.  Depending on how evil
> your movie-plot villain is (and how convoluted the plot will get), he/she
> could kill random strangers after photographing them with the victim, in order
> to fix a point in time.

Yeah, this seems like the best -- I make a video showing an interaction of the victim with the random strangers and then kill the strangers. The interaction part mitigates the "take a photo and then place victim in front of printout" attack.

I'm assuming a *very* evil villain, whose primary weakness are an inability to use photoshop / Gimp and a flair for overly complex plots.
He has, however read Peter's Evil Overlord List - http://www.eviloverlord.com/lists/overlord.html


> Peter.

"Go on, prove me wrong. Destroy the fabric of the universe. See if I care."  -- Terry Prachett 

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