Re: Card Playing Protocol

rarachel@prism.poly.edu writes about problems with card protocols,
>Anyway, you can ask him about it, his address is rvslyke@prism.poly.edu

I will once I am sure I will understand the answer.

Thanks,

-kb, the Kent who does have some reading ahead of him

--


Kent Borg                                                  +1 (617) 776-6899
kentborg@world.std.com                                
kentborg@aol.com                                      
          Proud to claim 35:00 hours of TV viewing so far in 1994!

Kent Borg wrote:
>I will once I am sure I will understand the answer.

Start out simple, just try something like a blackjack game (good
choice since the house strategy follows simple rules) over a
network.

The house shuffles, bit commits to the shuffle, and sends you the
hash.  Then, you can begin playing, or you can try to break the system
by finding a deck with a matching hash.  After you are done, the
casino sends you the deck and you can verify that you weren't cheated.

All sorts of other stuff can be added later, like digital cash, etc.

-- 
Karl L. Barrus: klbarrus@owlnet.rice.edu         
2.3: 5AD633;   D1 59 9D 48 72 E9 19 D5  3D F3 93 7E 81 B5 CC 32 
2.6: 088C8F21; 97 73 9E 8B 98 3E DD B5  E8 97 64 7E 20 95 60 D9
"One man's mnemonic is another man's cryptography" - K. Cooper

Karl Lui Barrus:
> The house shuffles, bit commits to the shuffle, and sends you the
> hash.  Then, you can begin playing, or you can try to break the system
> by finding a deck with a matching hash.  After you are done, the
> casino sends you the deck and you can verify that you weren't cheated.
> 
> All sorts of other stuff can be added later, like digital cash, etc.

Salting the deck before hashing it could prevent the above attack.
Hopefully not too many people will suggest this on the list. :)

Kragen