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SHA-256 + HMAC-SHA512

Provably Fair Verification Tool(2026)

Verify crypto casino game results with SHA-256 hash verification. Paste your seeds, check the math, know the game is fair.

2Algorithms
∞Verifications
100%Free
Evgeny Volkov (Senior iGaming Developer)Updated March 2026

Verify Game Result

provably-fair-verifier.sys

How Provably Fair Works

01

Before You Bet

The casino generates a random server seed and shows you its SHA-256 hash. This commits them to the result before you play.

02

You Place Your Bet

You provide your own client seed (or use a default). Combined with a nonce (bet counter), this creates a unique input for each round.

03

After the Round

The casino reveals the original server seed. You verify that SHA-256(server_seed) matches the hash shown before. If it matches, the game was fair.

CRYPTOGRAPHY

The Algorithm Explained

#1

Hash Function: SHA-256

SHA-256 is a one-way cryptographic function. Given the hash, you cannot reverse-engineer the seed. But given the seed, you can always reproduce the same hash.

#2

Game Result: HMAC-SHA512

The game result is derived from HMAC-SHA512(server_seed, client_seed:nonce). The first 4 bytes are converted to a decimal number, giving the roll result.

#3

Why This Is Secure

Because the casino commits to the server seed hash BEFORE you bet, they cannot change the outcome after seeing your bet. And because you contribute your own client seed, neither party controls the result alone.

FAQ

Provably Fair FAQ

Provably fair means you can mathematically verify that a casino game result was determined fairly and wasn't manipulated by the casino after your bet was placed.
Paste the server seed hash (given before betting), the revealed server seed (given after), your client seed, and the nonce into this calculator. If the SHA-256 hash matches, the game was fair.
Not on individual game results — the math prevents it. However, they could use a biased random number generator for seed selection. That is why reputable casinos use audited RNG systems alongside provably fair verification.
A random string generated by the casino for each betting session. Its SHA-256 hash is shown to you before betting. The actual seed is revealed after the session ends so you can verify results.
A random string you provide (or is auto-generated). It is combined with the server seed to determine the game result, ensuring neither party has full control over the outcome.
A counter that increments with each bet in a session. It ensures that the same server seed and client seed produce different results for each round.
Most crypto casinos including Stake, BC.Game, Roobet, and others offer provably fair verification. It is standard in Bitcoin and cryptocurrency gambling.
SHA-256 is used by Bitcoin and the US government. It is considered cryptographically secure with no known practical attacks. It would take billions of years to brute-force.
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Evgeniy Volkov

Evgeny Volkov

Verified Expert
Math & Software Engineer, iGaming Expert

Over 10 years developing software for the gaming industry. Advanced degree in Mathematics. Specializing in probability analysis, RNG algorithms, and mathematical gambling models.

Experience10+
SpecializationiGaming
Status
Active
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