pearlman@trw-unix.UUCP (Laura Pearlman) (12/21/83)
(I'm posting this to both net.games and net.games.pbm because it's a response
to an article responding to an article which appeared in net.games.pbm which
appeared in net.games. If you read the previous sentence five or six times
it will actually make sense...)
From Jonathan Biggar (sdcrdcf!jonab):
I have developed a method for playing simulation games over uucp
mail. It allows players to resolve dice rolls without any
possibility of cheating...
From Eric Holtman (whuxlb!eric):
Hmmm.. i remember reading about this in a paper on information
exchange, except that the game was called Mentel Poker... this
is net.games, not net.plagarism, guys......
Just how carefully did you read that "paper on information exchange"? If
you're talking about "Mental Poker" by Shamir, Rivest, and Adleman, then
you seem to be missing a few important differences:
1. It's not impossible to cheat at Mental Poker, if you use the Shamir's
scheme. Jonathan Biggar claims it is impossible to cheat using his scheme.
2. For Mental Poker, it's necessary that all the cards dealt are different;
that's not true with mental die rolls. In other words, you don't want two
aces of spades in play at the same time in poker, while it's perfectly legal
to roll two sixes on dice at the same time.
3. Shamir's scheme involves using one doubly-encrypted deck; Jonathan Biggar's
scheme seems to involve using two singly-encrypted "decks". This sounds a
little like a scheme described by Goldwasser and Micali in a paper called
(something like) "Probabilistic Encryption and How to Play Mental Poker
Without Revealing any Partial Information," but I really doubt that Jonathan
Biggar's scheme was based on that one, either...
4. The encryption method in Jonathan Biggar's article doesn't sound like
either Shamir's or Goldwasser's method. For Shamir's scheme, the two
players must use encryption functions which commute with each other, and
the Goldwasser-Micali encryption functions are much more complicated
than the ones sketched out in Jonathan Biggar's article.
Yes, there are similarities between Mental Poker and Mental Dice, but not
as many as there seem to be at first glance...
-- Laura Pearlman
...{decvax,ucbvax,sdcrdcf}!trw-unix!pearlman