Title: A Framework for Anonymous Lottery-Based Protocols in the Proof-of-Stake Setting Authors: Foteini Baldimtsi; Varun Rajeev Madathil; Alessandra Scafuro; Linfeng Zhou Key words: Proof of stake, Consensus, Privacy Abstract: In Proof-of-Stake (PoS) protocol, parties who are eligible to participate to the protocol are selected via a randomized process -- often called lottery -- that depends on the \emph{stake} that each party owns. The nature of PoS-based systems currently leaks the identity and stake of the elected party to all participants during the execution of the protocol which raises important privacy issues. In this paper, we present a modular approach for addressing the privacy leaks of lottery-based PoS protocols, with focus on consensus protocols. Our approach is to decouple the problem of implementing an anonymous lottery for selecting the participants, from the problem of implementing any other task in a proof-of-stake system. To show the modularity of our approach we present an implementation of an anonymous PoS consensus protocol inspired by the Algorand PoS protocol.