Rotate seeds to verify
The server seed is only revealed when you rotate to a new pair. Until then you can check the hash but not the results.
- Rotate after a session you want to check
- Save the revealed seed and your client seed
Provably fair casinos: check a result yourself, step by step
A provably fair casino commits to a secret server seed before you bet by showing you its hash. After you rotate seeds, it reveals the seed, and you can recompute every result from it, your client seed and a bet counter.
It proves the outcome was fixed before your bet. It says nothing about payouts, licences or third-party slots. Below: a worked example with real hashes, a verifier, the casinos listed as provably fair and what to check.
18+ only
Worked example with real hashes
In-house games only
By
Natasha Fernandez
Updated Oct 6, 2026
Short answer
What does provably fair mean?
The casino publishes a hash of its server seed before you play, you add your own client seed, and each bet uses a counter called a nonce. After the seed is revealed you can recompute any result and confirm the casino could not change it after your bet.
Covers
In-house games
Dice, crash, plinko, mines and similar originals that publish seeds.
Does not cover
Slots, live
Third-party slots and live tables rely on lab testing and the studio, not your seeds.
Does not prove
Payouts
A fair roll does not mean the casino will pay a withdrawal.
Change the client seed yourself before you play. If you keep the default, you rely on a value the casino chose.
Coverage
Which games you can verify yourself
Provably fair covers the casino's own games. Everything else needs the studio's certificate and the casino's licence.
| Game | Verifiable from seeds? | What stands behind the result |
|---|---|---|
| Dice, limbo, coin flip | Yes, at most casinos that offer them | The seed pair and nonce |
| Crash, plinko, mines | Yes, when the casino publishes the scheme | The seed pair, nonce and the casino's conversion formula |
| Third-party slots | No | The game studio's RNG and any testing lab certificate |
| Live dealer tables | No | Physical cards, wheels and the studio's procedures |
General pattern; each casino lists the games that publish seeds on its fairness page.
Limits
What provably fair leaves to you
The house edge stays
A provably fair dice game with a 1% edge still costs about $1 per $100 wagered on average. Fair means unaltered, not free of edge.
Licence still matters
LegalSeeds cannot force a payout. If a withdrawal is held, the licence and the casino's terms decide what you can do.
Provably fair Example data
How provably fair works, with a worked example
A common scheme used by seed-based dice games. Each casino documents its own variant on its fairness page.
- The casino commits Before your first bet it shows the SHA-256 hash of a secret server seed. Server seed hash (shown before play) b5ef15769b6f19703e6400f9c3dc3c397a369bafe82f61911591c180a970d6b0
- You add your seed You set a client seed; each bet adds a nonce counting from 0. Client seed · nonce ccr-pf-demo · 0
- The result is derived HMAC-SHA256 with the server seed as key and client:nonce:0 as message. HMAC-SHA256 output f63f97bd 769968de75afa80ceaf060ba45538b1affd992654afd20690078ad32
- Bytes become a roll The first four bytes become a float; times 10,001, cut to two decimals. First four bytes → float → result 246, 63, 151, 189 → 0.9619078480 → 96.20
- You check After rotating seeds the casino reveals the server seed; its SHA-256 must match step 1. Revealed server seed 14b181a157efd74a15d3a31be02dc3039db9097d921b05fe095e0a5891f2cdcd
What it proves
The casino fixed the server seed before you chose your client seed.
What it does not prove
That the casino will pay a withdrawal, or that third-party slots are fair.
| Nonce | HMAC (first 24 hex) | Bytes | Float | Result |
|---|---|---|---|---|
| 0 | f63f97bd769968de75afa80c… | 246, 63, 151, 189 | 0.9619078480 | 96.20 |
| 1 | 7aa6c0db8d02c068178305ab… | 122, 166, 192, 219 | 0.4791069541 | 47.91 |
| 2 | c235a20ebd2b3f278db87270… | 194, 53, 162, 14 | 0.7586308750 | 75.87 |
| 3 | a46b4ec4fe8661e3584baf70… | 164, 107, 78, 196 | 0.6422623852 | 64.23 |
| 4 | d33ac6d2e6a442216e25c999… | 211, 58, 198, 210 | 0.8251156104 | 82.51 |
Computed from the demo seeds shown. Casinos differ in message format and float conversion; follow the casino's own fairness page.
Checklist
Verify a bet in five minutes
Verify
-
Set your client seed Replace the default with your own random string before you play.
-
Note the hash Copy the hashed server seed shown before your first bet.
-
Play, then rotate Rotate seeds to reveal the old server seed.
-
Check the hash Hash the revealed seed with SHA-256 and compare it to the one you copied.
-
Recompute a result Enter the seeds and nonce in the verifier above or the casino's own tool.
Glossary
Provably fair terms
- Server seed
- The casino's secret random value, shown only as a hash until you rotate. So what: Its hash is the casino's commitment; save it.
- Client seed
- Your own value mixed into every result. So what: Setting it yourself stops the casino choosing both inputs.
- Nonce
- A counter that goes up by one with every bet on the same seed pair. So what: It lets you find the exact bet you want to check.
- HMAC-SHA256
- A keyed hash function that turns the seeds and nonce into random-looking bytes. So what: Anyone can recompute it, which is what makes the result checkable.
Provably fair FAQ
What is a provably fair casino?
A casino whose in-house games let you recompute each result from a server seed, your client seed and a nonce, once the server seed is revealed.
Do I need technical knowledge to verify?
No. Copy the hash before you play, rotate seeds afterwards, and paste the seeds into a verifier like the one on this page or the casino's own.
Can I verify on mobile?
Yes. The seeds are plain text, so any browser-based verifier works on a phone.
Can a provably fair casino still cheat?
It cannot change a committed result without the hash failing to match. It can still refuse or delay a withdrawal, which is why the licence and terms matter.
Does provably fair mean better odds?
No. The house edge is built into the payout table. A fair game with a 1% edge still costs about 1% of what you wager over time.
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