What is an RNG?
A Random Number Generator is a software algorithm that produces a continuous stream of unpredictable numbers. In a casino game, these numbers are mapped to outcomes — reel positions, card draws, dice rolls. A certified RNG ensures that every outcome is random and that neither the casino nor the player can predict or influence results.
Pseudo-random vs true random
Most casino RNGs are pseudo-random number generators (PRNGs). They use a mathematical algorithm seeded with an unpredictable value (such as system time in nanoseconds). The output is statistically indistinguishable from true randomness for practical purposes. True hardware RNGs exist but are less common in online gaming.
How RNGs are certified
Independent testing laboratories — including eCOGRA, GLI (Gaming Laboratories International), and BMM Testlabs — audit casino RNGs. They test the statistical distribution of outputs over millions of iterations to confirm the results are genuinely random and match the published RTP. NZ-licensed casinos must use RNGs certified by an accredited lab.
Provably fair games
Some online casinos use provably fair technology, which allows players to independently verify the fairness of each outcome using cryptographic hashing. Before a round, the casino publishes a hashed seed. After the round, the original seed is revealed. You can verify that the outcome was determined before your bet was placed.
What RNG certification means for you
A certified RNG means the casino cannot manipulate outcomes in real time. It does not mean you will win — the house edge is built into the game's design, not its randomness. What certification guarantees is that the game behaves exactly as its published RTP and rules describe.