Provably Fair Casinos

Author Tom Wilson


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Provably Fair Casinos

Aside from the obvious fear of losing money, the second most common concern for online casino players is whether the site has rigged its games. Although casino games are inherently skewed in favour of the house, we’re not talking about that here. We are referring to changing game results or tampering with them to increase the casino’s chances of winning without the players’ knowledge.

Until recently, players had no choice but to trust a casino’s claims that the outcomes of its games are truly random. There weren’t any surefire ways of knowing that the Random Number Generator (technology designed to facilitate randomness in casino games) wasn’t manipulated.

Third-party audits are a reliable indicator of a casino’s fairness, but who can guarantee that the casino won’t just change the code as soon as the inspection is complete? It’s impossible to know unless you play in a casino that uses provably fair software.

This technology was introduced with the rise of crypto casinos, enabling full transparency and verifiable results.

The system allows players to authenticate the result of each card shuffle, dice roll, slot or roulette spin. Essentially, it lets you check first-hand whether the RNG is functioning properly.

Here, we’ll explain what provably fair gambling is all about. You’ll learn how it works, how to use it, and where to find the best provably fair casinos.

Provably Fair Gambling: Getting Started

Let’s introduce you to a few terms that are inextricably linked to the provably fair system to help you understand how the software works:

  • Random Number Generator — RNG is the bedrock of online casinos. It’s a complex program code that online gambling sites use to ensure that each roulette or slot spin, dice roll, or card shuffle is completely random. By employing these tools, you can verify that the casino’s random number generator actually produced fair results during your gaming session.
  • Seed Generators — These are pieces of software that generate seeds or the starting point in the random number generation. It’s a number that triggers the whole process and determines the outcome. In fiat online casinos, players have no access to seeding numbers. In casinos using a provably fair system, users can generate their own seed number, which, in turn, allows them to check if the casino has tampered with the previous turn, dice roll, etc.
  • Hashing — Put simply, hashing is a process of transforming one value into another. In RNGs, it modifies the seed number and assigns a different value to prevent manipulation. Hash is a one-way function, so it can’t be reverse-engineered to obtain the original seed. Provably fair casinos use a cryptographic hash code to encrypt the seeded number generated by the casino for every bet.
  • SHA — SHA stands for secure hash algorithm and represents one of the many cryptographic hash functions. On casino sites, the cryptographic hash is essentially the algorithm generated with each round.

How Does Provably Fair Gambling Work?

Provably fair mechanisms vary from casino to casino, but the underlying principle for all single-player games is the same. Generally, the outcome of each spin, roll or shuffle is determined by the combination of three parameters:

  • Server seed — generated by the casino operator you’re playing with
  • Client seed — a product of the browser you’re playing on
  • Nonce — a variable that increases by one with each bet, which helps you keep track of your previous hands

Here is how it all works:

  1. Casino servers generate a seed number (server seed) before wagers are made, and the game round begins. You receive a hashed version of this seed prior to placing your bet. This hash contains the result of the game that you are about to play. This cryptographic hash is encrypted and unbreakable.
  2. After you (the player) generate your seed (client seed), the round starts. The purpose of this step is to enable you to check out the secret seed once you have finished playing.
  3. After the round is complete, the casino reveals the original seed. Using a trusted third-party calculator, you can confirm the results are random. You will know that the casino hasn’t manipulated the bet if the hash matches the server seed. Even if only one symbol in the seed is changed (for instance, if the casino were to try and tamper with the results), the algorithm will produce a different hash value.

Here’s a quick tip: Make sure your client seed is adjusted before you start playing. Using this method, you’ll prevent the casino from knowing it in advance.

Provably Fair Calculator: Verifying Roll Results

To confirm that the casino’s RNG indeed generates random results and that you’re not being scammed, you have to follow the steps below:

  1. The idea is to verify that the seed number you received from the casino matches the original seed’s hash. A third-party calculator such as Xorbin can be used to generate the server seed’s SHA256 hash.
  2. For verification, generate each roll result manually and compare it to the rolls you made on the casino site. This could take some time since you would have to verify dozens, hundreds, or even thousands of bets manually. Therefore, we recommend using provably fair verifiers.

Most online casinos that offer provably fair games use verifiers — programs that rely on nonces to calculate roll results more quickly. All you need to do is input the seeds and the number of bets you’ve made and let the verifier check the original hash.

After the verifier generates the list, you can compare it with the results of the casino. The casino operator didn’t tamper with the results, and all outcomes are fair if they match.

Is It Possible to Predict the Outcomes of Rolls in Provably Fair Systems?

Predicting the outcomes of future rolls or spins is next to impossible. This is because you are not given the unhashed (original) server seed before the game round ends —  only the hashed one. And with hash being a one-way, irreversible function, there’s no way to obtain the information about your upcoming hands.

What Games Are Provably Fair?

The technology is still not widely adopted, so provably fair games are scarce. Casino classics like dice and roulette (games with only one simple outcome) have been integrated into provably fair casino systems.

In multiplayer games like poker and blackjack, there are many variables that complicate things. It is theoretically possible to integrate any casino game into provably fair software. As the number of crypto casinos increases, we’ll see more and more provably fair games.

Final Thoughts

The concept of provably fair gambling, enabled by blockchain technology, is a game-changer in the online casino industry. For the first time, players can check the casino’s fairness and verify the randomness of game results. We anticipate a bright future for provably fair solutions based on the players’ reactions so far.


Author Tom Wilson

Chief editor and creator, Tom drives the direction of with the goal to provide the best and most honest resource for online gambling enthusiasts in Canada