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I am failing to find the article, but some early online poker systems used the server time as the seed coupled with a weak PRNG. With the information of the hole cards + community cards, after a few hands, could quickly determine exactly what seed was being used and perfectly predict everyone's cards.

by e28eta1 hours ago|

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I don't think this was the original source, but this paper matches your (& my) recollection: https://gwern.net/doc/cs/cryptography/2006-arkin.pdf

google surfaces a couple of HN posts, but the source (cigital.com) seems to be a dead domain at this point:

https://news.ycombinator.com/item?id=288138

https://news.ycombinator.com/item?id=9914607

It's a bad shuffle implementation + using time of day as seed (reducing search space). Using the player's 2 cards and the 3 flop cards, it finds the RNG seed in real time, and then future hands (on the same server) are solved in "under one second!"

by rogueaine12 hours ago|

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That’s not at all what the article proposed. The author constructed and transpose to the linear shift register coefficients and built a circuit network based on this to predict the next state (in the sandbox) and direct recipes.

by strstr12 hours ago|

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From the article:

> Sampling the current RNG through observations,

> Computing the current internal RNG state,

> Predicting the future internal states,

> Calculating corresponding quality levels for each future call, and finally

> Making use of the predicted levels with some adapters.

The entropy->seeds (internal RNG state) step took more math of course. Frankly, I wouldn’t be surprised if they could have extracted the seeds without the math with a bit of RE and memory inspection.

The version I did wasn’t predicting quality of course, it was predicting tie breakers