CRASH PROVABLY FAIR VERIFIER

No provably-fair game attracts more suspicion than Crash. The climbing rocket feels reactive — like it waited for your cash-out click before dying — but on a Stake-style casino the bust point is a pure function of the seed pair and nonce, fixed the moment you bet. The animation is theatre; the number is math. This page strips away the theatre and computes the number.

ONE GAME, TWO RIVAL SCHEMES

Before comparing numbers, know which Crash you played. Per-bet Crash (Stake, Shuffle) gives every player an individual outcome from their own seed pair — two people betting the same round see different multipliers. Hash-chain Crash (the bustabit lineage, used by several other operators) publishes one shared multiplier per round, derived by walking backwards along a pre-committed chain of SHA-256 hashes; every player in the round busts together. Both are legitimately provably fair, but their formulas are incompatible — a per-bet verifier will “refute” a hash-chain round that was perfectly honest. This tool speaks the per-bet dialect only.

HOW CRASH RESULTS ARE CALCULATED

Modern per-bet Crash (Stake-style) derives the bust multiplier directly from the HMAC-SHA256 hash of your seed pair and nonce:

1. Compute HMAC-SHA256(serverSeed, "clientSeed:nonce:0") → a 64-character hex hash.
2. Take the first 8 hex characters and read them as a 32-bit integer.
3. Apply max(1, floor( (2^32 / (int + 1)) × 0.99 × 100 ) / 100). The 0.99 is the 1% house edge.

Try it yourself with the reference vector: with server seed some server seed, client seed some client seed and nonce 1, the digest opens with 97887987, which reads as the integer 2542303623 and lands the rocket at 1.67x.

Important: crash formulas are not universal. This is the modern per-bet Stake-style formula. Some operators (bustabit-style) use a pre-generated hash chain instead, so always cross-check the number against your own casino's revealed round.

WHY VERIFY CRASH?

Because Crash is exactly where paranoia peaks. Instant 1.00x busts, a rocket that dies a tick after you doubled your stake, five sub-1.20x rounds in a row — all of it happens under an honest 1/x-shaped distribution, where low multipliers are simply common. Recomputing a suspicious round from the committed seeds settles the question with arithmetic instead of vibes: either the bust point follows from data fixed before your bet, or you have caught something real. In our experience it is virtually always the former — but that is the point of being able to check.

Two honest caveats. Verification cannot address the 1% edge baked into the 0.99 factor, and it cannot vouch for casinos running a different Crash scheme than the one you select. Our provably-fair primer covers the commitment cryptography; the multi-game verifier covers the other Originals.