  Ethereum 2.0 is a major upgrade to improve its scalability, throughput, and
security. In this version, RANDAO is the scheme to randomly select the users
who propose, confirm blocks, and get rewards. However, a vulnerability,
referred to as the `Last Revealer Attack' (LRA), compromises the randomness of
this scheme by introducing bias to the Random Number Generator (RNG) process.
This vulnerability is first clarified again in this study. After that, we
propose a Shamir's Secret Sharing (SSS)-based RANDAO scheme to mitigate the
LRA. Through our analysis, the proposed method can prevent the LRA under
favorable network conditions.
