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Degen Owl

Provably fair verifier

Check that a revealed server seed matches the hash you were shown before the bet. It runs in your browser and sends nothing anywhere.

Your bet

Nothing you type here is sent anywhere. The check runs in your browser.

The casino shows it after you change seeds.

64 characters, using 0-9 and a-f.

The seed on your side, exactly as the casino shows it.

The bet number under this pair of seeds.

Result

1. Was the seed fixed before the bet?

Not checked yet

Paste the revealed server seed and the hash you were shown before the bet.

SHA-256 of the server seed
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2. The raw digest for this bet

Message that is signed
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HMAC-SHA256, with the server seed as the key
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Before you draw a conclusion

  • No match? Check the seed and the hash for a missing or extra character first. Some casinos hash the seed in another way, so read their own instructions too.
  • It does not work out your roll, card or crash point. Each casino builds the message in its own way, and each game turns the digest into a result in its own way.
  • Compare the digest with the casino's own verifier. If theirs uses another message format, the two will differ, and that alone does not mean the game was unfair.

What this checks

In a provably fair game the casino picks a secret server seed before you bet, and shows you its SHA-256 hash. A hash is a fingerprint: the same seed always gives the same hash, and the hash does not give the seed away. Later the casino reveals the seed, usually when you switch to a new one.

  1. The commitment. The tool runs SHA-256 over the revealed seed and compares the result with the hash you were shown. If the two match, the seed was fixed before you bet and was not changed afterwards.
  2. The raw digest. The tool runs HMAC-SHA256 with the server seed as the key and clientSeed:nonce as the message. It shows the result as 64 characters of hex.

What this does not check

Step 2 uses one fixed message format. Casinos do not all use that format. They differ in the order of the parts, the character between them, and whether more parts are added. Each game also has its own way of turning the digest into a roll, a card or a crash point.

So this tool confirms the commitment and shows you the raw digest. It does not reproduce any casino's result. To check a result, use the casino's own verifier or the method it has published, and compare its digest with this one where the two use the same format.

  • A match only tells you something if you really saw the hash before you bet. Save it, or take a screenshot, before you play.
  • Some casinos hash the seed as text and some hash the bytes that a hex seed stands for. The tool tries both and tells you which one matched.
  • Provably fair means the result was not changed after you bet. It does not mean the game has no house edge.

A worked example

Press "Fill in the example" in the tool to load these values. They are made up for this page and belong to no casino.

  • Server seed: 54598a9962b6a6f2553a73b0c93a84e428d05dae014ebd120ae9db42a0923a79
  • Hash shown before the bet: ff54e47d3a4d5bc89541f7b15967676f1cda9065203d73fc8ffb50fc5268725a
  • SHA-256 of the server seed is that same hash, so step 1 says Match.
  • Client seed degenowl and nonce 1 give the message degenowl:1
  • HMAC-SHA256 of that message: 8e35d87c1ccdb552a08e48f165c8b324ee913ebf7543a952e242684ffe275196

Nothing leaves your browser

Nothing you type is sent anywhere. The hashing is done by Web Crypto, which is built into your browser, and this tool makes no request with your seeds. You can test that: load the page, switch off your connection, and the tool still works.

18+ only. These tools help you understand the odds. They do not beat them. Gambling carries real financial risk and is not a way to make money. Only bet what you can afford to lose, and get help from a local support service if it stops being fun.