What does provably fair mean?

Provably fair is a method that lets you check a roll after you bet. Before betting the site shows the SHA-256 (or similar) hash of its secret server seed. You supply a client seed. Each bet uses the next nonce (bet number). After a seed rotation, the site reveals the server seed so you can confirm that it matches the hash and that each roll follows from the three inputs. Verification confirms that the roll was not changed after the bet. Try the interactive verifier demo on the home page first.

What are server seed, client seed and nonce?

Input Who controls it When you see it
Server seed The site As a hash before betting, in full after rotation
Client seed You (or the site’s default) Before betting
Nonce Counts up by one per bet Shown with each bet

How do I verify a roll step by step?

  1. Copy the commitment. Before betting, save the server seed hash.
  2. Place your bets with a known client seed and note the nonce of the bet you want to check.
  3. Rotate the seed so the site reveals the old server seed.
  4. Hash the revealed server seed with the same algorithm and confirm it equals the commitment.
  5. Recompute the roll using the site’s documented formula, then compare it with the roll shown for that bet.

Worked example (generic scheme)

This example uses the demo scheme on our home page. Every site’s algorithm differs, so use the site’s own verifier for real bets.

  • Server seed: example-server-seed-do-not-use
  • Commitment, SHA-256: 5985679beff8d3f3e994a7d1805b3ba3ee93a8440d7b4c9315f1f246f5c64dda
  • Client seed: my-client-seed, nonce 1, message my-client-seed:1
  • HMAC-SHA256(server seed, message): de685dfd3d081db8f1174afabddc53857f1344f6d43237b4ed9ed75f9fa25127
  • First 8 hex characters: de685dfd = 3,731,381,757
  • Roll: floor(3,731,381,757 / 2^32 x 10,000) / 100 = 86.87

Nonce 2 gives 17.12 and nonce 3 gives 2.06 with the same seeds.

How does a real site do it?

Methods differ. PLG.BET documents HMAC-SHA512 of “client seed-game id” keyed with the server seed, uses the first five hex characters and repeats until the value is below 1,000,000 (see our PLG.BET review). CSGO500 describes a global server secret that rotates every 24 hours, with its SHA-256 hash shown while in use (see the CSGO500 review). We have not run a dice verification on either site; see each review for details.

When should I change my client seed?

Any time. Changing the client seed makes later rolls depend on a value the site could not have known earlier. On many sites, changing it also rotates the server seed and reveals the old one, which lets you verify past bets.

Can a provably fair site still be a scam?

Yes. Provably fair covers roll integrity. It does not cover withdrawals, licences or how the site treats your money. Read are CS GO dice sites legal and safe for scam signals, and see how fairness is weighted in our methodology (25%, the largest criterion).

Tip: Save the commitment hash before you bet. A site that only shows a hash after the fact proves nothing.