Math doesn't lie. Your audience can verify any draw is fair in 30 seconds.
🔐 Public SHA-256 proof on every draw · 9,800+ draws since April 2026
We commit to the participant list + seed + timestamp via SHA-256 BEFORE picking a winner. Once published, manipulation is mathematically impossible.
Every draw gets a permanent URL at sorteigram.app/verify. Paste the hash, see all inputs. Anyone can audit.
Our selection algorithm is open-source on GitHub. You can audit not just one draw — you can audit the entire system.
Brands with reputation on the line trust Sorteiogram. Cryptographic proof = no PR disasters from rigged giveaway accusations.
Participant list + seed + timestamp locked at hash-time. Hash published immediately, BEFORE any winner is chosen.
Algorithm: SHA-256 hash interpreted as big-endian integer, modulo participant count, gives winner index. Deterministic from public inputs.
Auditor takes published hash, recomputes the winner index, checks it matches the announced winner. Takes 30 seconds.
Verification URL never expires. Years later, anyone can still audit your historical giveaways.
SHA-256 is a one-way cryptographic hash. Given input X, we compute hash H(X). Given H(X), it's computationally infeasible to find another input Y with H(Y) = H(X). This means: once we publish H(participants+seed+time), we're committed to those exact inputs. Then the winner is computed deterministically from H(X). No manipulation possible without rewriting math.
Mathematically: the giveaway runner cannot manipulate the result without publicly breaking the cryptographic commitment. Practically: anyone can verify the draw was fair, even years later, without trusting us.
No. The seed is committed in the SHA-256 hash BEFORE the draw. If we changed it, the published hash wouldn't match the recomputed hash — auditors would catch it immediately.
It can't. The participant list is included in the hash. Once published, locked. Any later change invalidates the hash.
Honestly, because it's hard to engineer and most users don't ask. But once you start using provably-fair, you can't go back. Audience trust is too valuable.
Math doesn't lie. Your audience can verify any draw is fair in 30 seconds.
Run Provably-Fair Draw →