Long-range attacks on PoS blockchains and the related “I still work here” attack in BFT-based blockchains are among the major security issues in these systems. Recently, an approach has been proposed to deal with these attacks by anchoring BFT/PoS membership into Ethereum’s proof-of-work blockchain. As Ethereum is abandoning PoW, this approach is no longer viable. This project aims at achieving the same goals using Bitcoin’s PoW.