How Random Number Generators Work to Keep Games Fair

Here at Spin Rio we bring you a huge collection of games to play. One concern that every gambler shares is that of whether the games are fair or not. It is entirely fair that players will not just take our word for it. Here we answer all of your questions and explain exactly how we ensure that our games are fair and you have a real chance of winning.

RNGs: The Beating Heart of Online Casinos

A piece of technology called a Random Number Generators (RNGs) ensures that our casino games are fair. RNGs are algorithms that generate a sequence of numbers without any discernible pattern, making every game outcome completely random and fair.

In the world of online casinos, RNGs are the unseen heroes that ensure every spin of a slot reel, every card dealt in blackjack, and every number called out in roulette is entirely random. This randomness is paramount for an authentic casino experience as it guarantees the games' fairness and unpredictability.

RNGs can be broadly classified into two types: Pseudo RNGs (PRNGs) and Hardware RNGs (HRNGs). PRNGs are software-based algorithms that generate a sequence of numbers that seems random, starting from an initial value known as a seed. On the other hand, HRNGs are physical devices that generate random numbers based on a naturally occurring physical process, such as radioactive decay. While most online casinos primarily use PRNGs, HRNGs often serve as a backup to handle hardware failure scenarios

Ensuring RNG Integrity: iTech Labs Certification

The important question for players is how can they trust that these RNGs are indeed random and not manipulated? This is where independent testing agencies such as iTech Labs come in. iTech Labs, a leading RNG testing company globally, regularly audits Spin Rio's RNGs. The audits ensure that the RNGs are operating correctly and generating truly random and unpredictable results, thereby providing a fair gaming environment.

iTech Labs' evaluation process for RNGs involves an exhaustive series of tests. These tests verify various aspects, including statistical randomness, internal state, seeding, re-seeding, cycling, unpredictability, non-repeatability, and usage of random numbers. This includes both scaling and shuffling, crucial for different game types like card games and slot games.

For PRNGs, iTech Labs conducts a three-stage evaluation process. They begin by examining the source code and identifying the RNG algorithm used. They verify the internal state of RNG, check for unpredictability and non-repeatability requirements, and verify seeding, background cycling, and minimal re-seeding. Once these are verified, the RNG code is compiled, and the raw numbers generated by the RNG algorithm are subjected to “diehard” tests. In the final stage, they generate a sample scaled output and apply “Chi-square” tests.

In the case of HRNGs, the first stage involves the evaluation of the specifications of the device, researching any weaknesses that may be present, and evaluating the code for hardware RNG failure detection and failover. The second and third stages involve tests that determine statistical randomness, unpredictability, and non-repeatability of the RNG.

Upon successful completion of RNG testing, iTech Labs provides a certification report outlining the evaluation conducted and the results. They also provide test results for Diehard and Chi-square tests, a certification seal/logo to be placed on the gaming site, and a linked certificate indicating compliance of the RNG with the tests carried out.

Common Misconceptions about RNGs

A prevalent misconception is that if a slot game hasn't paid out a big win in a while, it's "due" for a jackpot. This belief stems from a misunderstanding of how RNGs work. Each spin of the reels is an independent event, and the outcome of one spin has no influence on the next. This is why you can have two jackpot wins in a row or go a long time without a significant payout.

Another common misconception is that RNGs can be manipulated by casinos to increase their profits. Independent audits by iTech Labs and other testing agencies ensure that RNGs are fair and not manipulated. Their audits guarantee that each game's outcome is statistically random and unpredictable, thereby ensuring a fair gaming environment.

RNGs and Casino Games: A Closer Look

Now, let's delve into how RNGs work in specific casino games.


Slot machines, both physical and online, are the most straightforward application of RNGs. In a traditional slot machine, each reel might contain around 20 symbols. When you pull the lever or press the spin button, the machine uses an RNG to select a random number for each reel. These numbers then correspond to a specific symbol or blank space, and that's what you see when the reel stops spinning.

In the online world, slot games can have hundreds or even thousands of potential outcomes for each reel, meaning there are millions of possible combinations. It's also important to note that the outcome is determined as soon as you press the spin button. The spinning reels and suspenseful music are all for show - your fate has already been sealed by the RNG.


Blackjack, one of the most popular card games in casinos, also relies heavily on RNGs in the online setting. When a new game starts and the deck is shuffled, the RNG comes into play.

In a physical game of blackjack, the dealer manually shuffles the deck to randomize the order of cards. In the online world, an RNG performs this task. For each card in the deck, the RNG will generate a random number which is then associated with a card. When a card is 'drawn', it's actually the RNG selecting a random card from the ones remaining in the deck.

This ensures that each game is fair, with the outcome of one hand having no effect on the next. It's like playing with a freshly shuffled deck every time.


Roulette is another game where RNGs are integral to ensuring fairness. In a physical game of roulette, the dealer spins the wheel in one direction and spins the ball in the other. The pocket in which the ball lands is completely random, determined by physics and chance.

In online roulette, the spinning of the wheel and ball are animations, but the outcome is determined by an RNG. When you press the spin button, the RNG generates a random number between 0 and 36 (for European roulette) or between 0 and 37 (for American roulette). Each of these numbers corresponds to a pocket on the wheel, and that's where the ball lands.

Each spin is an independent event, just like in a physical roulette game. This means that the outcome of one spin doesn't influence the next, ensuring a fair and unpredictable game.


In online poker, RNGs are used to shuffle and deal the cards, ensuring a fair game. When a hand begins, the RNG generates a random number for each card in the deck. These numbers correspond to the order in which the cards are dealt. As players fold or cards are discarded, the RNG continues to generate numbers to deal new cards from those remaining in the deck.

RNGs also come into play in the distribution of community cards in games like Texas Hold'em and Omaha. The randomness provided by the RNG ensures that the game is fair and that players can't predict which cards will be dealt next.

Guaranteed Fair Gaming at Spin Rio

Now that you understand how RNGs work, you should feel confident in the fairness of our games. Whether you want to play slots, our table games, video poker or anything else, you can be sure that the games are not rigged and you have a fair chance of winning. Why not head over to the casino today and start playing your favourite games safe in the knowledge that a win really might be just around the corner.


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