Provably Fair
Maktub supports two cryptographic fairness modes that allow players to independently verify that every game outcome was generated honestly and was not tampered with.
Why Provably Fair?
Traditional online casinos require players to trust that the operator is not manipulating outcomes. Provably fair systems eliminate this trust requirement by using cryptographic proofs that anyone can verify.
Every bet in Maktub produces a set of verifiable data that the player can use — either manually or through an automated tool — to confirm the outcome was predetermined before the bet was placed.
Supported Modes
Maktub offers two fairness modes. Operators choose which mode to use when configuring their platform.
Classic RNG (HMAC-SHA256)
The industry-standard approach used by most provably fair platforms. It uses a commit–reveal scheme with HMAC-SHA256 to generate deterministic random numbers.
Best for: Operators who want a well-understood, widely-adopted fairness model that players are already familiar with.
EC-VRF (Elliptic Curve Verifiable Random Function)
A next-generation approach based on RFC 9381 (ECVRF-ED25519-SHA512-ELL2). It produces a cryptographic proof alongside every output, making verification more direct and mathematically rigorous.
Best for: Operators who want the strongest possible fairness guarantees with built-in cryptographic proofs for every single bet.
Comparison
| Feature | Classic RNG | EC-VRF |
|---|---|---|
| Algorithm | HMAC-SHA256 | ECVRF-ED25519-SHA512-ELL2 |
| Standard | Industry convention | RFC 9381 |
| Verification timing | After seed rotation | Per-bet (immediate) |
| Server secret | Server Seed (hex string) | Ed25519 Private Key |
| Public commitment | SHA-256 hash of server seed | Ed25519 Public Key |
| Per-bet proof | No (hash commitment only) | Yes (VRF Proof + Output) |
| Player-visible data | Hashed Server Seed, Client Seed, Nonce | VRF Public Key, Client Seed, Nonce, VRF Proof, VRF Output |
Verification Data
Regardless of the mode, each bet stores the data needed for verification. Players can access this data through the Provably Fair modal in the game UI.
Classic RNG fields
- Server Seed (Hashed) — SHA-256 hash of the server seed, shown before the bet
- Client Seed — Player-provided or auto-generated seed
- Nonce — Auto-incrementing counter per seed pair
EC-VRF fields
- VRF Public Key — The server’s Ed25519 public key
- Client Seed — Player-provided or auto-generated seed
- Nonce — Auto-incrementing counter per seed pair
- VRF Proof — 80-byte cryptographic proof (hex)
- VRF Output — 64-byte hash output (hex)
Seed Rotation
Both modes support seed rotation, allowing the player to change their client seed at any time. When seeds are rotated:
- Classic RNG: The previous server seed is revealed, allowing retroactive verification of all bets made with that seed pair. A new server seed is generated and its hash is shown.
- EC-VRF: The current VRF public key is shown, along with the next VRF public key. Since EC-VRF provides per-bet proofs, players can verify each bet immediately without waiting for rotation.