# How Slot Machines Work

The security properties of these pseudo-random generators will generally be that, even when the attacker can observe polynomially many outputs from such generators, it won't be feasible to guess the next output with a probability much better than random guessing. Thus the results of physical play are not sequential. Each of the 64 stops on the virtual reel corresponds to one of the 22 stops on the actual reel. To avoid the feeling that the player's money is simply ebbing away whereas a payout of credits on a single line machine would be bets, and the player would feel they had made a substantial win, on a 20 line machine, it would only be 5 bets and would not seem significant , manufacturers commonly offer bonus games, which can return many times their bet. The casino operator can choose which EPROM chip to install in any particular machine to select the payout desired.

## Functions of the RNG

I have heard it is illegal for a slot machine to deliberately have too many near misses. Can you tell me what you know about this? To answer your question I asked a well connected gaming consultant and he said Nevada regulations state that one stop on a reel can not be weighted more than six times more than either stop next to it. So if a jackpot symbol were weighted by 1 and both bordering blanks were weighted by 6 then there would be 12 near misses for every one time the reel stopped on the jackpot symbol.

This would be the maximum allowed near miss effect. My own results detailed in my slot machine appendix 1 back up this theory well. The red double seven was the highest paying symbol and I saw the blanks above and below it about 5 to 6 times as often: This is not a game theory question, but I figured since you answer dating questions you might handle this.

I had a dream recently where I sat down at an open slot machine. I told him it was my machine and hit the cash out button and gave him his ticket. He said he had his eye on the machine and since he had his money in first it was his machine.

I turned to call a slot attendant and while I was doing that he put his money in again, pushed the button and hit a jackpot. In my dream we then had an argument over who gets the money, the person who clearly had the machine and intended to play it or the person who unsolicited put the money in the machine.

I realize this is a bizarre situation but who do you think would win the argument? My understanding is that the person who is pressing the buttons gets the money. I asked Brian, who helped with the last question, about this. Here is what he wrote, which I agree with. In the scenario described, the person who put in the money and pressed the buttons would receive the jackpot. What I find interesting about this question is the paradox that in all likelihood, the jackpot never would have occurred without this chance encounter.

As you know, the random number generator in the slot machine is continuously working even when the machine is not in play. So even though one patron feels cheated, their run-in ultimately led to pressing the spin button at that exact millisecond when the RNG was on the winning combination.

So, if one patron had acquiesced, there is never a jackpot to fight over. I have used your site to knock down myths and betting systems with many friends and your proofs always win the day.

On the Pink Panther and some others there is a bonus round that presents a screen with pictures from which to pick. Behind some are coin amounts and others have a symbol that ends the bonus round. Once you are presented with the bonus board the placement of the symbols cannot be changed, can they? Thanks for helping in the fight against betting systems.

However, I know many people in the industry and those I trust pretty much are in agreement on this topic. That said, it is my understanding that in all forms of electronic games, including video slots, video poker, and video keno, the outcome is usually determined the moment you make your decision. For example, players can now bet money straight from a credit account, rather than dropping coins in for every pull. Players can also keep track of their wins and losses more easily, as can the casinos.

The operation is also simpler in modern machines -- if they want to, players can simply press a button to play a game, rather than pull the handle. One of the main advantages of the computer system for machine manufacturers is that they can easily configure how often the machine pays out how loose or tight it is.

In the next section, we'll see how the computer program can be configured to change the slot machine's odds of hitting the jackpot. How to Play Craps.

How to Play Blackjack. How to Play Roulette. How to Play Video Poker. You pull the handle, and the computer records the next three numbers from the random number generator. The first number is used to determine the position of the first reel, the second number is used for the second reel and the third number is used for the third reel. Security by obscurity i. An insider attack is all it takes to break the system. However, using fast hash functions makes sense if speed is a concern.

From what I've read, slots and the like continually generate random numbers even when not being played. The number chosen is based on when the button is pressed; thus, the security of the RNG is relatively unimportant. There was I video horse racing game in Australia a few years ago that suffered from bad seeding. During the time when the game was not in use it showed a "demo" version of a horse race. Except that the demo version turned out to be what was in use when you played the game.

Thus you already knew which horse had won. How disappointing to see a highly up voted answer recommend Mersenne Twister. It is not cryptographically secure: That's a serious problem for a gambling machine. Also, the claims about "no direct visibility" are baloney: Just because you have transformed the output of a non-secure PRNG somehow, does not necessarily make it secure. I hope no one will follow the advice in this answer. Dec 19 '13 at The mod example for bringing a random number generator result into a certain range is usually a bad idea, as it can introduce bias.

Very interesting although the degree of free argument is flawed. If you do not re-seed between shuffles you will eventually hit every deck combo.

In any case I definitely up-voted your answer and particularly appreciate the practical points and experience with the application. In practice it probably doesn't matter, but in theory it's nicer to have every shuffle to be possible.

The real problem with MT is that given a relative small sample of outputs you can calculate the internal state. Your first link redirects to a page which says "Not Found". I know it has been a while PolyThinker 4, 15 I don't think it is necessary for the PRNG to be cryptographically secure.

The seeding is the more important part. I try to address this in more detail in my answer. B-B-S is exactly what should not be used: BBS failed all of the statistical tests we have conducted and is therefore not suitable for stochastic simulations. Jeff, stuff like BBS has the advantage that their security can be proven with proper assumptions even when the algorithm itself is known.

FryGuy 7, 2 25 PRNGs are much faster and somewhat safer because they don't fail in the same way as hardware devices. A good solution is to use hardware devices to seed the PRNG. A PRNG design like Fortuna allows you to continuously mix in entropy from the hardware, but is still safe if the hardware fails.

They should be, but in practice that is definitely not the case, particularly on older machines. As of May 24, , here is a summary of the rules a RNG must follow: Static seeds cannot be used.

You have to seed the RNG using a millisecond time source or other true entropy source which has no external readout anywhere on the machine. This helps to reduce the incidence of "magic number" attacks The RNG must continue generating numbers in its sequence at least times per second when the game is not being played. This helps to avoid timing attacks RNG outputs cannot be reused; they must be used exactly once if at all and then thrown away. Multi-system cabinets must use a separate RNG and separate seed for each game.