The 2018 International Symposium on Information Theory and Its Applications (ISITA2018)


Session Number:Mo-PM-1-4



How to generate transparent random numbers using blockchain

Yuto Ehara,  Mitsuru Tada,  


Publication Date:2018/10/18

Online ISSN:2188-5079


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Nowadays, we can enjoy many internet applications including online lotteries and games. The results of lotteries, card games, dice throwing and so on, depend upon the values of random numbers generated under some rules. However, we cannot verify the correctness for the given random numbers, that means, we have no means to convince ourselves that the given random numbers have indeed been correctly generated, using a pre-determined algorithm, and without being intentionally perverted by anyone. We say that such random number generation can provide ‘transparency’. It is quite important that random numbers given online can convince us that those are correctly generated. In other words, the transparency of online random number generation is quite important. Sako et. al. [5] have given a random number generation scheme applicable to the game ‘Backgammon’, in which transparency of blockchain enables us to verify the correctness for used random numbers after the game ended. In that scheme, however, the server has to be a trusted party, and it means dishonest generation of random numbers is possible by making one player and the server corrupted. In this paper, we present a transparent random number generation scheme. To be sure that a few trusted parties appears in the description of the scheme, but by implementing such trusted ones with public blockchain actually operated, our scheme can generate transparent random numbers without requiring any trusted parties.