Re: Online poker RNG...

On 18 Feb 2006 16:49:23 -0800, "Gerry" <gerald_helmling@xxxxxxxxx>
wrote:

Two points.

Yes, _if_ someone knows the _exactly_ what algorithm is being
used, and it has a 32-bit seed, then it's theoretically
possible to predict the next card after you've seen six
cards, and possible to narrow things down a bit after seeing
five. But that requires knowing exactly what algorithm is being
used; just knowing that it's a 32-bit seed is not enough.

Second, if I were playing online poker for money this
would be the least of my worries, because there are much
easier ways to cheat. For example collusion - if two
players agree to support each other's plays that gives
them an advantage (because it effectively means their
betting limit is twice that of the other players'.)
It wouldn't be too hard for one person to arrange to
be playing two hands (presumably the site would notice
two players at the same IP address so it would maybe take
a little trickiness.)

I'm hoping someone(s) on here will be kind enough to help ease my mind
(or, for that matter, to verify my reasons for concern!) And I should
say that, while I'm a good poker player, I'm only a marginal student of
mathematics and computing, so keep that in mind, please, as you answer
this question, but:

Is it possible that, as I'm playing online, any of the other players
are cheating by way of predicting the order of the cards in the
"shuffled" deck?

A few (some math, some poker) truths to keep in mind as you answer:

1. Many sites use an RNG algorithm based on 2^32. Isn't that pretty
easily susceptible to brute-force attacks from someone who has a
program relying on distributed computing?

2. In the most popular type of online poker (Texas Hold 'Em), there are
four rounds of betting, and the most important three rounds come AFTER
(a) each player gets two (face-down) cards and (b) three face-up cards
are dealt on the table -- SO, if the cheateer is, say, the third player
to be dealt cards at a table of ten players, then he will know the 3rd
and 13th cards (i.e. the two cards he's been dealt) as well as the
21st, 22nd and 23rd cards (the three dealt face-up immediately
following the two distributed to each player).

So, I guess my question is: how easily would someone be able -- either
by brute-force run-through of all possible combinations of "deck
arrangements" with those 5 cards in those specific spots, or by some
sort of reverse-engineering, or whatever -- to conclude the sequence of
cards in the deck (which, of course, would give him knowledge of
everyone's cards, as well as the two cards left to be dealt)?

And, for that matter, a related question: there's a piece of software
currently on the market (Check out pokerrng.com.) which claims that, if
a player enters into the software the details of a few thousands
recently dealt hands, the software will "synch" with the poker system's
RNG well enough to predict three of the five cards (not suits, but
values, which is enough to be dangerous!) left to be dealt! Is this
even plausible? Do I need to be afraid of this type of thing?

Anything online has inherent pitfalls, and cheating is -- both online
and offline -- a fact of life, but there's a certain level of security
I'd like, and I wonder if I'm jumping at shadows or rightly
concerned...

Any thoughts would be appreciated!

Thanks,

Gerry


************************

David C. Ullrich
.

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