01
Commit
Before the round kicks off, the operator generates a fresh server seed and publishes its SHA-256 hash. The raw seed is locked away, no one, not even the trading desk, can read it, swap it or backdate it.
Provable fairness, in plain English
Every round on a Duel original comes from a seed pair you can verify offline, right from your own couch. The casino can't know the result before you do, and you can prove it wasn't changed after the fact, which is worth knowing when you're weighing up an offshore site from Australia.
02
Mix
Your client seed (you pick it) and a per-round nonce are mixed with the locked server seed using HMAC-SHA-256. The 64-byte digest that pops out is the deterministic source of every game outcome.
03
Reveal
Once the round resolves, the raw server seed is published. Re-hash it on your own machine, confirm it matches the original commit, recompute the HMAC and check the outcome byte-for-byte.
# Verify any past round in 60 seconds.
import hmac, hashlib
server_seed = "d6f1...4a2c" # revealed after round
client_seed = "my_seed_42" # yours
nonce = 128
digest = hmac.new(server_seed.encode(),
f"{client_seed}:{nonce}".encode(),
hashlib.sha256).hexdigest()
# first 5 bytes -> game outcome (e.g. dice roll 0–99.99)
print(int(digest[:8], 16) % 10000 / 100)Mechanics in detail
From a single click to a verifiable round
Three inputs feed every result: a server seed (committed and hashed before the round), a client seed (you choose it), and a nonce (a counter that ticks up). After the round, the raw server seed is revealed so you can recombine the inputs and reproduce the outcome bit-for-bit.
Verifying a round in 60 seconds
From the in-game settings, copy the seed pair and nonce of any past round. Drop them into any HMAC-SHA-256 calculator, a one-line Python script or an online tool, and recompute the digest. The first bytes map to the game outcome; match them against the casino's published result and you've verified the round yourself, no trust required.
Why and when to rotate seeds
Rotating your client seed kills off any prediction a third party might try to make about future rounds. After a long session, or any time you switch device, open settings and rotate. The old server seed becomes verifiable straight away, and a new one is committed before your next round.
Provable fairness FAQ
Can the casino still rig outcomes?
No, not on the originals. The server seed is hashed and shown before the round; once it resolves, the unhashed seed is revealed. If the casino had swapped the seed mid-round, the hash wouldn't match and the round is void by protocol.
Are third-party pokies provably fair too?
The pokies from outside studios use certified RNGs audited by independent labs (eCOGRA, GLI, iTech Labs), but they aren't provably fair in the cryptographic sense, you trust the audit rather than reproducing a single spin. Provable fairness is currently exclusive to the in-house originals.
What happens if my verification does not match?
Open a support ticket with the round ID and your recomputed digest. If the published result doesn't match the maths, the round is void and the wager is refunded in full. It hasn't happened in production, but the policy is unconditional.
Does provable fairness improve my odds?
No, it guarantees the maths you signed up for. The published RTP and house edge are the real long-run returns; provable fairness just removes any doubt that the casino is quietly running them lower.