SRNG: An Efficient Decentralized Approach for Secret Random Number Generation

Many blockchain protocols and applications require access to a reliable source of distributed random numbers. This has led to the recent interest in the study of distributed random number generation (RNG) and randomness beacons. Numerous approaches have been proposed in the literature, using different cryptographic techniques and working under different assumptions. A problem that has recently been studied is that of generating secret random numbers. There is a natural usecase for this. Suppose a casino CASSIE wishes to offer its gambling games as a smart contract. It is not viable to generate a fresh distributed random number for each bet. Instead, a secret random number should be generated at predefined intervals, e.g. each day, and used as a seed to create the randomness for the whole day. This seed should only be known to CASSIE. Moreover, at the end of the day, CASSIE should be able to disclose the seed and prove that there was no tampering. In this work, we propose a simple and novel distributed random beacon protocol that generates distributed random numbers while preserving secrecy. The generated random number can be used in DeFi applications, such as decentralized casinos, for some time, until it is published along with proof that it is indeed the output of our random beacon. In addition to achieving the desired secrecy property, our approach is also efficient and requires the same amount of computation and communication as non-secret random beacons. Our protocol can easily be implemented as a smart contract.