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All software producers for online casinos claim their games are based on the latest random number generators (RNG) that guarantee an unpredictable outcome.

However, can you be that sure that RNG can not be decrypted? The answer may be surprising.

Let's sort out the operation principles, types of RNG, and specifics of use in online casinos.

What is a random number generator?

Let's begin with a theoretical definition:

Random number generator is a device able to return absolutely unpredictable sequences of numbers, not connected to each other in any way.

In case dice or reels used in different lotteries are primitive RNGs.

We can divide RNGs into 2 major categories:

  1. Generators of truly random numbers (hardware RNG);
  2. Generators of pseudorandom numbers. 

The first category includes models that use the data of chaotic variations of particular physical processes. For example, the data source can be atmospheric, shot, or thermal noises.

Hardware RNGs are too expensive and complicated for the producers of casino games, so they use pseudorandom numbers. It is software designed to generate sequences of numbers.

No matter how complicated the algorithm is, it doesn't return truly random numbers. This is why such random number generators are called pseudorandom. They adopt the baseline figure and change it to return a new one with the help of numerous mathematical operations.

All video slots and other casino games without dealers are based on this kind of RNG.

Why do casino operators won't use the exact name? The answer is obvious:

No adequate marketing specialist will suggest using "pseudo" in the description of the device supposed to provide fairness and security.

Does it mean casinos trick the customers and manipulate with games outcome? Let's refrain from such strong statements and try to sort out the situation instead.

How does the RNG work in casino games?

We have described the random number generator operation's details on the example of the famous Red, White & Blue slot by IGT in "How the RNG-based slots work" at Casinoz.

We have a short explanation for those who don't feel like getting into details. The RNG returns figures in a vast range. They then transform into the sets of numbers related to particular symbols. These symbols appear on the slot's screen.

RNG-based online blackjack and roulette work in a similar way.

The RNG works continuously, returning a huge number of figures every second. This is why you shouldn't be upset if somebody wins a high payout on the slot right after you. Chances you winning it are slim.

Do casinos intervene in the RNG operation?

If the random number generator is nothing more than software, it raises the question:

Can casinos fabricate the outcomes of the games?

Players are left to rely on the software producers' fairness, the honesty of gambling operators, thoroughness of regulators, and audit organizations' professionalism.

This is why you should always choose trustworthy online casinos powered by licensed software from famous producers. Supervision of legal authorities and independent experts won't hurt either.

If you play in a doubtful online casino that doesn't report for work, you act at your own risk.

The history of gambling knows cases when gambling operators were found guilty of fraud.

  • In 2008, Norman Clem suspected he'd been cheated in World Wide Wagering. Playing craps by Pass Line and Don't Pass Line, he fixed the outcomes of 3200 rolls. It turned out he won only in 27% of cases, while the RTP was supposed to be about 49%.
  • The scandal with BLR software captured the headlines.
  • Michael Shackleford, the founder of WizardOfOdds.com, found out the producer has been artificially increasing the house edge with a simulator's help.

Be careful and don't trust little-known developers and operators.

Who controls the operation of RNG?

Several companies that certify random number generators are famous in the gambling world. The most reputable are eCOGRA, TST, and iTechLabs.


They execute comprehensive audits, including the operation of RNG. Then they certify the products that meet their quality criteria. Usually, online casinos publish copies of the certificates on the websites.

Besides, famous software producers don't allow casino operators to intervene in random number generators' operation. Of course, this is about licensed software.

You can be sure the RTP is a particular slot is the same in all casinos where it is presented. This is a matter of the developer's credibility, which is a big deal for the leading brands.

Is it possible to decrypt the RNG algorithm?

Let's see if it's possible to hack a random number generator and predict the outcomes of the games?

As the RNG is nothing more than software, theoretically, it can be hacked. But is it that easy to decrypt it? Almost certainly not.

Best software developers use powerful pseudorandom number generators based on extremely complicated algorithms. Chances to decipher them are slim.

However, failures happen time after time. Especially if the hackers act in an unexpected way.

In the 90s', Ronald Harris was working in the Gambling Authority of Nevada. One of his duties was finding errors in the slot software. He modified several slots in the way they landed winning combinations in certain circumstances. His partner only had to follow instructions while playing. Harris ended up behind bars.


Could pseudorandom number generators be considered secure?

Totally. They return results that can't be predicted.

Can you trust the casinos do not intervene in the RNG operation?

Make sure you choose trustworthy online casinos with a great experience and perfect reputation. They won't give a reason to doubt their fairness.

What do you think about it? Please share your opinions and experience in the comments, and don't hesitate to ask questions.

Frequently asked Questions

How does a random number generator work in casino games?

This is an algorithm that continuously generates sets of random figures. Combinations of these figures define the outcome of the game.

Can casino operators intervene in the RNG operation?

They can't if they use licensed software from famous providers.

Who certifies the RNG?

Famous audit organizations do it.

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