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Blockchain Based Verifiable Random Number Generator
Open Algorithm
Open Source
Open Participation
Results Recorded on Public Blockchain
No Manipulation Possible
Cryptoeconomics Ensures No Collusion


Randao is based on Blockchain technology and provides the service of random number generation that is open source, decentralized, socialized and verifiably fair.

Randao not only has the characteristics of uncontrollability and unpredictability which it inherits from the common random number generator, but also is more accessible and provably fair. Randao helps individuals to observe their impact on the generation process of random numbers through providing each stakeholder participation channel. The transparent, irreversible generation process ensures the fairness of the random numbers.

With the Randao service, users can quickly build a verifiably fair application for different scenarios, for example, public management, entertainment, sports, finance, and corporate management.

Lucky draw, e.g. U.S. green card lottery and Beijing license-plate lottery, is a common way for government to allocate public resources. Fairness, especially verifiable fairness, is undoubtedly the most critical requirement the lottery must meet. Randao is a provably fair service, due to its strong communication characteristics, it can help participants to reach a consensus more efficiently and to eliminate misunderstandings. With Randao, government can host lotteries in which the process is transparent and the results can be audited.
Random Tax Auditing
If people want to get lucky in lottery, they definitely don’t want to be luckily picked and checked by authorities if they are cheating the law. In this kind of case, e.g. random tax auditing, the result will only influence the participants who are randomly selected and the participants normally do not challenge the selection process. This leaves a huge space for manipulation. Under this situation, using the provably fair Randao service ensures the fairness of the process and the results and eventually reduces the overall management cost and improves governments’ credibility.
Sports Competition
How to group a tournament or assign a position in a sport competition in some ways is the most influential determinant of who wins and loses the game. Traditionally grouping draw methods are constantly challenged by both participants and audiences because they are neither transparent nor auditable. Using Randao, we can implement these key points: 1. participants who want to have some influence on the results can choose to participate in the random number generation process; 2. participants should fulfill their obligation and offenders will be punished; 3. the process is transparent; 4. the results can be audited.
Online Gaming
Fairness is probably the most important aspect when players decide whether they will participate a given online game. Traditionally, Gaming operator proves its fairness by showing certificates it obtains from a “trusted” third party. Obviously, the fairness is solely depended on people’s confidence in the third party which is not always reliable. With Randao, game players and operators do not need any third party to prove the fairness. Instead, the whole random number generation process and result are verifiably fair.

Randao Commit/Reveal Source Code made its debut on GitHub ( It was then cited by many academic and engineering papers as the most viable random number generator on public Blockchain.
Randao Commit/Reveal Smart Contract 1.0 deployed on Ethereum testnet and mainnet (
Q3 2017
Randao technical whitepaper and Website ready for public access.
Q1 2018
In addition to the Commit/Reveal algorithm, the BLS algorithm will be implemented as an alternative random number generation service, which provides higher RNG throughput.
Q2 2018
Randao smart contracts, mining bot services, DApps will be released to Ethereum mainnet.
Q3 2018 ~
Randao services deployment on other public Blockchains and community building based on those services.