Secure verifiable randomness improves blockchain lottery fairness
Verifiable Randomness for Blockchain-Based Lottery Systems
Cryptography and SecurityComputers and Society
Summary
Lotteries on blockchains need random numbers that everyone can trust, but it’s hard to make sure those numbers aren’t tampered with. The paper looks at old methods of generating randomness and points out their weaknesses, especially when the last participant tries to cheat by not revealing their number. The authors propose a new system that fixes this problem, based on a commit-and-reveal process, and test it on a real blockchain network. This new method is easy to use, low-cost, and provides a fair way to get random numbers on-chain.
What this means in practice
- •For blockchain developers: Build fair lottery or game systems that use on-chain random numbers resistant to participant manipulation.
- •For online gaming companies: Integrate a low-cost, verifiable on-chain randomness source into blockchain-based gambling products for greater player trust.$Commercial implications: Enables blockchain casinos or lottery platforms to offer provably fair games with transparent randomness guarantees.
Authors
Gonçalo Ferreira, André Zúquete, Paulo Bartolomeu
Abstract
As lotteries and other high-stakes decentralized applications increasingly depend on unpredictable randomness for their operations, the lack of a secure and transparent on-chain random number generator that is verifiable by all participants remains a critical open problem. Various approaches to blockchain-based random number generation have emerged over the years, each with their own strengths and limitations, and have consistently been superseded as blockchain technology evolved. This paper surveys existing approaches to on-chain randomness and proposes a new platform that builds upon the well-known commit-and-reveal scheme while directly addressing its principal vulnerability, the last revealer attack, in which the final participant can withhold their reveal in order to bias or abort the output upon seeing an unfavorable result. We further compare this solution with prior approaches and evaluate its entropy properties. The proposed architecture combines a web-based front-end with a Solidity smart contract deployed on the Polygon 2.0 blockchain. Implemented and tested on the Amoy testnet, the prototype is low-cost and simple to deploy, providing a practical, accessible proof-of-concept for verifiable on-chain randomness.