Debunking Misconceptions About RNGs At Online Casinos

Published on 11 Mar 2019 by Mason Jones
RNGs and pRNGs at Online Casinos

All gambling depends on the randomness of the outcome. In land based casinos, the randomness is visible in the spinning of the roulette wheel, or the shuffling of the cards at the blackjack table. However, in online casino gaming, the randomness is simulated and hidden in the mathematics of the software. This means that online casinos do not make use of a true random number generator. This is true, even for the best no deposit bonus casino which can be found online. This has always been a cause for concern for many people. It is true that online casino software uses a pseudo random number generator (pRNG) and not a true RNG. The article examines whether this affects the fairness of the process.

True Random Number Generation

True random number generation depends on a physical event that cannot be predicted. Despite the laws of physics being involved, one cannot predict the outcome of a roulette wheel in a landbased casino. There are too many unpredictable factors involved, factors that cannot be replicated spin after spin.

Four Reasons Why Land Based Roulette Outcomes Cannot Be Predicted


Angle at which the ball is thrown


Speed at which the ball is thrown


Speed at which the wheel is spun


Number on the spinning wheel nearest to the croupier when the ball is thrown

However, the physical roulette wheel was ‘hacked’ once by Joseph Jagger, a British engineer, in the 1870s. He saw that machines showed bias because of wear and tear and figured that this would apply to roulette wheels as well. His evaluation of the wheels at the Beaux Arts Casino in Monte Carlo showed that on one of the wheels had a bias. He exploited the bias and won £60,000 (over £3 million in current value) before the casino got wise.

It is now not possible to repeat what Jagger did because these days the gaming machines are made much more resistant to wear and tear. The machines are replaced at prescribed intervals and machine suppliers keep coming up with improved versions.

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True RNG and Online Gaming Software

Random Numbers

Online gaming software is based on simulation. True RNG needs a physical device. Hardware driven software has been created. An example of such a device is explained below.

  • A physical phenomenon that is truly random, like thermal noise, is the input source.
  • It is measured and translated into a binary number sequence that is truly random.
  • This can then be used by any simulation software.

But such a system is not suited for online casino software. The physical measurement and translation renders it very slow. In addition you have thousands of players hooked up on an online casino server, each independently playing the games. The response time needs to be instantaneous and totally electronic.

Until something more advanced comes along, pRNG is the best option on offer.

What Is Pseudo About pRNG?

Since many readers will not have a mathematics background this is being kept simple, with apologies to those who know more.


The process starts with picking a number, any number. It will not be a number like ‘7’ or ‘164’, but a much bigger number.


A defined algorithm performs some extremely complex calculations on that number to arrive at an output, which is the first random number of the series.


This number becomes the input for the next set of calculations resulting in the next random number. And so on.


In online gaming software these random numbers are converted to outputs, like one of the 52 cards of a deck, or one of the 33 numbers of a European Roulette wheel. Again the algorithm for this is extremely complex.

So, Why Is This Process Pseudo?

  • The random numbers are not generated, but are created.
  • If you have access to the starting number and know how the algorithm works then you can theoretically predict the next number.

Why Is This Pseudo Process Acceptable?

In practice it is impossible to carry out the prediction due to the complex nature of the algorithm. The actual process in online casino gaming for each number takes less than a split second, which may be less than the time required for sensory cognition.

The animation on your screen of slots reels spinning (and the equivalent in other games) is just to create a realistic effect. The outcome is decided as soon as you activate the start button. So there is not enough time as well.

But there is a practice in place that provides total security against hackers. At randomly chosen intervals the sequence is broken. The input for the next calculation is not the output from the previous one. It is a different number altogether. Then the algorithm moves on a different track till the sequence is broken again. Tracking of outcomes becomes impossible.

Random Number Generator

Fair Gaming is Important for the Online Casino Industry

Those involved in the online casino industry as operators, software providers or administrators know that their survival depends on perception and reputation. Whether you're look for no deposit slots or a quick round of roulette, casinos know that the fairness of their games is vital. When online casinos were launched in the mid-1990s, many people stayed away because they feared that the software could be manipulated.

Consequently the software not only had to be fair, but demonstrably so. This lead to independent verification of the RNG used in the software.

Fair Gaming Reports

  • The RNG is verified by an independent expert agency at the software provider end.
  • When the casino operator applies for a licence in any jurisdiction, the RNG is again independently verified and a certificate issued to the operator.
  • The certificate is time bound. This means that the audit has to be repeated periodically for the renewal of the RNG certificate and the casino licence. This also ensures that the operators have not tampered with the RNG.

The main agencies that perform the audit of the RNG are listed below.

Detective work

  • eCOGRA
  • Technical Systems Testing (TST)
  • Price Waterhouse Coopers (PWC)

As a player you also have some responsibilities:

The brain of a gambler

  • Before you sign up at an online casino, check if the RNG certificate icon is displayed at the web site.
  • Clicking on the icon should link to the actual certificate that should be on the web site of the auditor. This ensures that the operator is not posting a bogus certificate.
  • Check to see whether the certificate is valid.


The development of RNGs is a work in progress. We have come a long way from the time engineers and statisticians used printed random number tables. The software developers are creating more complex algorithms to ensure that hacking is not possible. The auditors are devising more stringent tests to verify the fairness of the RNG.

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