Provably Fair CheckerHMAC-SHA512

Gamdom Provably Fair Verifier

Gamdom's provably-fair engine is built on HMAC-SHA512 rather than the SHA-256 most casinos use, with its own message format and per-game decoding. This tool implements Gamdom's actual scheme so Dice, Mines, Plinko, Keno, Limbo and Blackjack reproduce byte-for-byte.

8 games at Gamdom

Seed pair

Client seed

Server seed (unhashed)

Nonce

Runs entirely in your browser - your seeds never leave this device.

Roll Result

00.00

0255075100

Provably fair verification lets anyone independently recompute a game's result from its server seed, client seed and nonce - confirming the casino could not have altered the outcome after the bet. Browse all casinos & games

How Gamdom provably fair works

Gamdom computes HMAC-SHA512 with the server seed as the key and clientSeed-nonce as the message. The wider 64-byte output gives each round more raw entropy than a SHA-256 design, and Gamdom's games slice it in game-specific ways.

Dice reads the hash in ten-hex-character windows, rejecting values above one trillion to keep the distribution flat, then reduces modulo to a 0-999999 roll. Mines turns four-hex floats into a draw-without-replacement of bomb tiles. Plinko maps a uniform value through a binomial cumulative-distribution table to pick the landing bucket, and Blackjack deals from a 32-card representation.

The server seed is committed before the bet, so Gamdom cannot rewrite a result afterwards. Rotate seeds to reveal the server seed and verify any past round here.

Gamdom's provably-fair games

Gamdom's per-user provably-fair games - Dice, Mines, Plinko, Keno, Limbo and Blackjack - are all reproducible above. Gamdom also runs shared chained games (Crash, Roulette, Hilo) on a rotating seed model that sits outside a per-bet verifier.

How to verify a Gamdom result

1Open the Provably Fair or Fairness panel in your Gamdom account.
2Rotate your active server seed to reveal the previous seed unhashed.
3Copy the server seed, your client seed and the nonce.
4Paste them above and select the Gamdom game to compare the result.

Gamdom provably fair FAQ

What algorithm does Gamdom use?⌄

HMAC-SHA512 - keyed by the server seed over the message clientSeed-nonce. That is a wider hash than the SHA-256 Stake uses, so a standard Stake verifier will not reproduce Gamdom results.

Is Gamdom provably fair?⌄

Yes for its per-user games. Each result is bound to a server seed Gamdom commits to before you bet, and this tool re-derives it from the revealed seed so you can confirm fairness.

Why is Gamdom different from other casinos?⌄

It hashes with HMAC-SHA512 and decodes each game its own way - ten-hex windows for Dice, four-hex floats for Mines, a binomial table for Plinko. The verifier encodes those exact rules.

Can I verify Gamdom Crash or Roulette here?⌄

No. Those use a shared, rotating seed chain rather than your personal seed pair, so they are outside a per-bet verifier. Dice, Mines, Plinko, Keno, Limbo and Blackjack are fully checkable.