Tom Brand, M.Sc. Thesis Seminar
Advisor: Prof. Yuval Ishai
Bitcoin was introduced to the world in 2009 with Proof of Work (PoW) Leader Election as one of its novel building blocks. Since then, much criticism has been made of its high energy consumption. Proof of Stake protocols aims at replacing PoW protocols as a much more efficient version while still maintaining its security properties under the Honest Majority model.
In our work, we show a bribery attack under the Rational Majority model, which breaks the persistence security property of the underlying protocol. Furthermore, we show how this attack can be conducted on a specific protocol - Ouroboros Praos. Finally, we propose a solution for making it as secure as PoW protocols.