{"id":28318,"date":"2026-11-09T09:57:14","date_gmt":"2026-11-09T09:57:14","guid":{"rendered":"https:\/\/www.quantumrun.com\/consulting\/?p=28318"},"modified":"2026-11-09T09:57:14","modified_gmt":"2026-11-09T09:57:14","slug":"provably-fair-cryptography-commit-reveal","status":"publish","type":"post","link":"https:\/\/www.quantumrun.com\/consulting\/provably-fair-cryptography-commit-reveal\/","title":{"rendered":"Provably Fair Cryptography Explained: How Commit And Reveal Works In A Live Crypto Casino"},"content":{"rendered":"

For most of the internet’s history, online games of chance have run on a simple bargain: the player trusts the operator. A random number generator runs on a private server, and the only reassurance available is a certificate from a testing lab.<\/p>\n

A different model has spread through the crypto economy over the past decade. Known as provably fair, it replaces institutional trust with a check that any user can run. Looking at how it works in a real deployment shows both what the approach achieves and where its limits lie.<\/p>\n

\"Provably<\/p>\n

The trust gap in digital chance<\/h2>\n

Physical games carry their own evidence. You can watch a shuffle or see dice land. Online, every outcome is a number produced by software, and even an honest operator struggles to prove that a particular result was not altered after a bet was placed.<\/p>\n

The conventional answer is the audit. Independent labs test random number generators and certify that outcomes match the expected distribution over millions of samples.<\/p>\n

Audits are useful, but they are aggregate rather than per round; they describe software at a moment in time, and they still ask the user to trust both the auditor and the operator.<\/p>\n

Commit and reveal<\/h2>\n

Provably fair systems are an application of a cryptographic pattern called commit and reveal. One party commits to a secret value by publishing a fingerprint of it, then reveals the value later so anyone can confirm it was never changed.<\/p>\n

The fingerprint is produced by a cryptographic hash function, usually SHA-256, the same family of functions used in blockchains and password storage.<\/p>\n

Two properties make it suitable. It is practically impossible to reconstruct the input from the output, and changing a single character of the input produces a completely different output. A published hash therefore locks in a value without revealing it.<\/p>\n

The three inputs<\/h2>\n

Most implementations combine three values.<\/p>\n