provablyunfair.com - can you beat it ?

[knowitnothing]

Hi there again,

This time I'm presenting a site that is mostly for illustration purposes, you can access it at provablyunfair.com but you can't play with bitcoins there.

What's the deal there ? Very simple, you get to play a game with 50% chance to win, except that it has a very simple form of pattern matching. It will try to guess your next bet, after some initial bets. How many games can you play before getting a horribly low win ratio ? The next result is known in advance, which you can check after each game.

What's the point of this thing ? This is an illustration of why one has to take care when betting (like if gambling games being -EV wasn't enough) at some places. It is possible that in the future there will be other illustrations, for now there is just this simple one there.

What data is being collected ? The only data used are the bets you placed after visiting the site. If you reload the site, that data is erased.

Enjoy!


EDIT: Forgot to mention that I can arrange ads to be placed there, provably unfair casinos might get a good deal with that domain.

[FloatesMcgoates]

I get the point you are trying to make here, that casinos can rig these "provably fair" setups "in their favor." However, I have taken your "provably unfair" dice game, ran it nearly 800 times, and have achieved a near 75% win rate by finding an input combination that defeated whatever algorithm you are using in order to try and give the house an advantage. This can be seen here:



Anyway, my point is that it would be wiser for a gambling website to actually implement soundly "provably fair" dice rolls in order to rely on mathematically sound principles to gain them money, rather than attempt to con a few extra coins here and there but be exposed to any one individual messing their entire operation by finding a way to defeat their cheat.

Edit: With over 1500 rolls, the results are as follows:


Showing that if a casino wanted to rig their rolls, they would need to do some substantial predictive behavior research beforehand else have their bankroll ran on.

[b!z]

Very interesting website, knowitnothing. I think it explains to people very clearly why provably fair gambling is important.

If you like, you can link to our article Provably Fair Gambling Explained.

[knowitnothing]

Now you can actually break the casino, it has an artificial bankroll starting with 100k units. As soon as it gets to < 1000 coins, then it is broken and you can no longer bet. Note that the edge here is 0%.

The only point I'm trying to make here is that there are certain setups which are likely to not favour the player. Observe, and this is very important, that in this situation you're aware that the casino is rigged. And I bet you would be surprised by how simple the current algorithm is. If I find some extra time I could try improving this, but it will always be subject to the players knowing it is rigged which then makes them trying to find out how the algorithm fails.

[dudeami]

Well, think I did some damage :p

Got it down to -82000, then either the algo changed or it started acting different. All I did was simply choose left/right, then click w/e won the first round twice, then alternate 11 times (this method isn't guaranteed at 15+ bets).

Screenshots:

100%: http://i.gfxtub.com/7897ab.png
92%: http://i.gfxtub.com/7815b1.png

I basically did that a lot, doing 1U bet for the first, then max for the rest, never more than 14 bets, then refresh (sorry if I hit your servers too hard!)

Did I beat it? :p

[FloatesMcgoates]

From earlier in the day:

[aksplace]

We will gladly add a bounty if your able to debunk and prove any claimed provably safe site is operating in this way. It's the best interest of all players, companies, and us included.

[knowitnothing]

From earlier in the day:

Looking good. Somehow it recovered from that loss, until..

Well, think I did some damage :p

Got it down to -82000, then either the algo changed or it started acting different. All I did was simply choose left/right, then click w/e won the first round twice, then alternate 11 times (this method isn't guaranteed at 15+ bets).

Screenshots:

100%: ..
92%: ..

I basically did that a lot, doing 1U bet for the first, then max for the rest, never more than 14 bets, then refresh (sorry if I hit your servers too hard!)

Did I beat it? :p

You did do some good damage there. As you noticed, it is mostly deterministic so if you repeat the pattern you keep winning. Playing few times definitely beats it as it doesn't try to link your current session to any of your previous sessions, so it can't even have a chance of collecting a greater amount of data.

The algorithm takes a different route after hitting those levels, but it is still trying to figure out what you are likely to bet next. So it's a matter of finding out what kind of change took place.

The server told me it's fine, btw, keep hitting

If you guys could go ahead and beat it for good, i.e. make it lose more ~26k units, then I could put up some notice about it going bankrupt and maybe announce a new experiment in some time.


PS: My replies will take long to occur.