This is not a theoretical explanation. This page walks through the verification of a real game round played on Duelbits, using actual seeds and hashes from a genuine Blackjack Original bet. You can follow every step yourself and confirm the result, no trust required.
For the general explanation of how provably fair works, see the How to Verify Fairness with Provably Fair page.
🎯 The Round We Are Verifying
This bet was placed on Duelbits Blackjack Original on 10 September 2026. Here are the exact values from the Fairness panel:
Server Seed Hash (shown before the round):
d5b0b05db9fc07db2f31c00d1127b6ab10e93774dd86c8d680eb1e9dd3f96688
Server Seed (revealed after cycling):
8d8ae667b5a92043ce166fa661e3d833fca4407700c9665db8f29ce0b85253f8
Client Seed:
5rdccq5t
Nonce:
1
Game: Blackjack Original
Bet: $1.00
Result: Win (+$2.00)
These are real values from a real account. Nothing has been edited, fabricated, or cherry-picked.
🔐 What Are We Proving?
Provably fair verification answers one critical question: was the game outcome determined before the bet was placed, and was it left unchanged afterwards?
The server seed hash is shown to you before you play. It is a one-way cryptographic fingerprint of the server seed, you can see it, but you cannot reverse it to find the original seed. After the round, the actual server seed is revealed. If hashing the revealed seed produces the exact same hash you were shown before the round, this proves:
The server seed existed before you bet
It was not changed after you bet
The outcome derived from it was locked in from the start
🧪 Step 1: Verify the Server Seed Was Not Changed
This is the most important step. Take the revealed server seed and hash it using SHA-256. If the result matches the server seed hash that was shown before the round, the seed was genuine and unaltered.
Revealed server seed:
8d8ae667b5a92043ce166fa661e3d833fca4407700c9665db8f29ce0b85253f8
Hash it using SHA-256. You can do this with any of these methods:
Option A - Online tool:
Go to any SHA-256 generator (search "SHA-256 hash online"). Paste the server seed into the input field. Click hash/generate.
Option B - Command line (Mac/Linux):
Open Terminal and run:
echo -n "8d8ae667b5a92043ce166fa661e3d833fca4407700c9665db8f29ce0b85253f8" | sha256sum
Option C - Command line (Windows PowerShell):
[System.BitConverter]::ToString((New-Object System.Security.Cryptography.SHA256Managed).ComputeHash([System.Text.Encoding]::UTF8.GetBytes("8d8ae667b5a92043ce166fa661e3d833fca4407700c9665db8f29ce0b85253f8"))).Replace("-","").ToLower()
The result you will get:
d5b0b05db9fc07db2f31c00d1127b6ab10e93774dd86c8d680eb1e9dd3f96688
Compare this to the server seed hash that was shown before the round:
d5b0b05db9fc07db2f31c00d1127b6ab10e93774dd86c8d680eb1e9dd3f96688
They match. This confirms the server seed was created before the bet was placed and was not altered afterwards. Duelbits could not have changed the outcome after seeing the bet.
✅ What This Proves
The hash match proves the outcome was locked in before the round started. Here is why this matters:
If Duelbits had changed the server seed after your bet to manipulate the outcome, the hash of the new seed would be completely different from the hash you were shown, SHA-256 produces a totally different output for even a single character change
Because you also contribute your own client seed, Duelbits could not have predicted the final outcome either, they committed their seed before knowing yours
The nonce ensures every round is unique even when the seeds stay the same
No trust is required. The maths is the proof.
🔢 Step 2: Recalculate the Game Outcome
Once you have confirmed the server seed is genuine (Step 1), the next step is to combine the server seed, client seed, and nonce through the same algorithm Duelbits uses and recalculate the exact game outcome.
For this Blackjack round, the three inputs are:
Server seed:
8d8ae667b5a92043ce166fa661e3d833fca4407700c9665db8f29ce0b85253f8Client seed:
5rdccq5tNonce:
1
The algorithm combines these values, hashes the result, and maps the output to game-specific outcomes, in this case, the deck order for Blackjack, which determines every card dealt during the round.
This recalculation can be performed using third-party provably fair verification tools that support Duelbits' algorithm. These tools take the three inputs, run the same hash-to-outcome conversion, and show you the resulting card sequence so you can compare it to what you saw during the game.
The Duelbits fairness page provides additional technical detail on the algorithm.
🎮 How This Works Across Different Games
The verification process is identical for every Duelbits Original, the same three inputs (server seed, client seed, nonce) go through the same SHA-256 process. The only difference is what the output maps to:
Crash → the crash point multiplier
Dice → the roll result (0.00–99.99)
Blackjack → the deck order (card sequence)
Mines → mine placement positions on the grid
Plinko → the path of the ball
Roulette → the winning number
Keno → the drawn numbers
Hi-Lo → the card values in sequence
Dice Duels → each player's roll result
Duel Poker → the dealt cards
Step 1 (hash verification) proves the outcome was predetermined. Step 2 (outcome recalculation) proves it maps to the correct result. Together, they provide a complete, end-to-end proof that the round was fair.
📋 How to Verify Your Own Bets
You can verify any of your own Duelbits Original bets using this same process:
Open any Duelbits Original game.
Click the Fairness icon (shield icon in the game interface).
Note your Active Client Seed, Active Server Seed Hash, and Total Bets (Last Nonce).
Play one or more rounds.
When you are ready to verify, click Cycle next to "Next Client Seed", this reveals your current server seed and moves it to the Previous Seeds tab.
Go to the Previous Seeds tab and click Reveal to see the full unhashed server seed.
Hash the revealed server seed using SHA-256 and compare it to the hash you were shown before the round.
Optionally, use a third-party verification tool to recalculate the game outcome from the three inputs.
Cycling your client seed is harmless, it does not affect your gameplay, odds, or balance. It simply rotates to a fresh seed pair and unlocks verification of the previous one.
⚠️ Important Notes
You can verify at any time: There is no expiry on previous seeds, they remain in the Previous Seeds tab for you to check whenever you want.
Cycling is required: The current server seed cannot be revealed while it is active (otherwise you could predict future outcomes). You must cycle to a new seed pair before the previous one can be verified.
Step 1 is the critical proof: Even without running the full outcome recalculation, confirming the hash match proves that the outcome was predetermined and unaltered. This is the step that establishes trust.
Any SHA-256 tool works: You do not need special software. Any online hash generator, command-line tool, or programming language with SHA-256 support will produce the same result, that is the entire point of a standardised algorithm.
❓ Frequently Asked Questions
Can I verify this right now?
Yes. Copy the revealed server seed from this page, hash it with any SHA-256 tool, and compare the result to the server seed hash listed above. You will get an exact match.
Does cycling my client seed affect my odds?
No. The odds and house edge are identical regardless of which seed pair is active. Cycling simply rotates to a fresh pair and reveals the previous server seed for verification.
Why can't I see the server seed before cycling?
Because revealing the active server seed would allow you to predict outcomes for future rounds. The seed must remain hidden while active, that is what makes the system fair for both sides.
What if the hashes do not match?
If the hash of the revealed server seed does not match the hash you were shown before the round, that would mean the server seed was changed, a provably unfair outcome. This has never occurred on Duelbits, and the hash chain system makes it structurally impossible without detection.
Can Duelbits manipulate which rounds I verify?
No. You choose when to cycle and which rounds to verify. Duelbits cannot know in advance which rounds you will check. And because the hash chain links all rounds together, manipulating any single round would break the chain and be detectable across every subsequent round.
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