Seed, hash and nonce: glossary of provably fair terms
A server seed is secret data the game fixes before a round. A client seed is a value the player can supply. A hash is the fingerprint of the server seed shown in advance, and a nonce is a counter that changes the result each round. Together they let a result be re-checked afterwards.
Server seed
The server seed is secret data generated by the game operator before a round, or before a series of rounds. It is one of the inputs that determine the result, so it must stay hidden until the result can no longer be changed. After that the operator reveals it.
Hash
A hash is a fixed-length fingerprint produced from data by a one-way calculation. The same data always gives the same hash, and changing one character gives a completely different one. The operator shows the hash of the server seed before bets are taken, which commits it to that seed without disclosing it.
Client seed
The client seed is a value the player can set or accept. It is mixed with the server seed so the operator does not control all of the input. It adds protection only if the player can change it and the result truly depends on it.
Nonce
A nonce is a number that goes up by one each round. Because it is combined with the same two seeds, it makes every round produce a different result without needing a new seed each time. Seeing the nonce in a round record tells you which round of the series you are checking.
Putting the terms together
After the seed is revealed, a verifier hashes it again and compares the output with the hash shown earlier. It then combines the server seed, client seed and nonce using the game's published formula to reproduce the result. The full method and its limits are in what provably fair means in crash games.
A match shows the result was not altered after commitment. It does not show the draw was random in the statistical sense, which is the job of a random number generator and its certification. Regulation 45(2) of the Conduct of Gambling Operations Regulations, 2026 requires that generator to be certified by the Authority or its approved agent. A match also says nothing about the price of the game, which is covered under RTP and house edge.
Gambling is addictive: play responsibly, and only if you are 18 or older.
Questions and answers
What is a server seed?
It is secret data chosen by the game operator that feeds into the result of a round or a series of rounds. Its hash is published first and the seed itself is revealed later.
Why does a client seed matter?
Because the player contributes part of the input, the operator cannot choose all of the data alone. It only helps if the player can change it and the final result really uses it.
Does a matching hash prove the game is fair to play?
No. It shows the revealed seed is the one committed to earlier. It does not show how generous the game rules are, and it does not replace the certification of the random number generator that Regulation 45(2) of the Conduct of Gambling Operations Regulations, 2026 requires.