Guides from The Verification Lab
Plain-English documentation for "provably fair" games: what the proof covers, what it leaves out, and how to verify a result yourself with SHA-256 and HMAC — in your browser or a few lines of Python.
# commitment published before play
sha256(server_seed)
a5e39de9361cb47d…e1ac582d ✓ match
# roll = HMAC-SHA256(server_seed, "client:nonce")
hmac(seed, "lab-reader-01:0")
c6b1e6abfb75912f…
int(0xc6b1e6ab) / 2^32 × 100
roll = 77.61Provably fair lets you check that a result wasn't changed after you bet. It doesn't prove good odds, honest payouts or a safe site. Here's the line between the two.
The three inputs behind every provably fair result: what each one does, who controls it, when it's revealed, and how changing one changes the outcome — with computed examples.
Fifteen checks that separate a fairness claim you can verify from a badge you can't, with a scoring table, examples of what each failure looks like, and what to do next.
A complete worked verification: check the commitment, compute HMAC-SHA256, turn hex into a 0–99.99 roll and map it to a dice or case outcome — every value computed and shown.
How a hash chain lets a crash-style game commit to millions of rounds at once, how to verify a round links to the next, and how a hash becomes a multiplier — with computed values.
| Guide | Topic | Words | Code blocks |
|---|---|---|---|
| What provably fair means — and what it doesn't prove | Basics | 1111 | 1 |
| Server seed, client seed and nonce, explained with real hashes | Basics | 1110 | 1 |
| Red flags in "provably fair" claims: a 15-point checklist | Red flags | 1078 | 0 |
| How to verify a case or dice roll step by step (HMAC-SHA256) | Verify | 997 | 6 |
| Hash chains explained: how crash-style games commit to every round | Verify | 1027 | 2 |
We document how provably fair systems work and how to check them. We don't rank sites, name operators or promise wins. A valid proof shows a result wasn't changed after the fact; it does not make a game good value. Gambling means you should expect to lose the money you put in. 18+ only. Responsible gambling