Babylon: Reusing Bitcoin Mining to Enhance Proof-of-Stake Security

TL;DR

Babylon leverages Bitcoin's extensive hash power to improve Proof-of-Stake security by providing timestamping and checkpointing services, enabling secure, energy-efficient blockchain operations with formal security guarantees.

Contribution

The paper introduces Babylon, a novel platform that reuses Bitcoin's hash power to enhance PoS security through timestamping and checkpointing, with formal cryptoeconomic security proofs.

Findings

Babylon achieves zero additional energy cost via merge mining.

Provides formal security guarantees for PoS protocols.

Enhances PoS security against long-range attacks and censorship.

Abstract

Bitcoin is the most secure blockchain in the world, supported by the immense hash power of its Proof-of-Work miners, but consumes huge amount of energy. Proof-of-Stake chains are energy-efficient, have fast finality and accountability, but face several fundamental security issues: susceptibility to non-slashable long-range safety attacks, non-slashable transaction censorship and stalling attacks and difficulty to bootstrap new PoS chains from low token valuation. We propose Babylon, a blockchain platform which combines the best of both worlds by reusing the immense Bitcoin hash power to enhance the security of PoS chains. Babylon provides a data-available timestamping service, securing PoS chains by allowing them to timestamp data-available block checkpoints, fraud proofs and censored transactions on Babylon. Babylon miners merge mine with Bitcoin and thus the platform has zero additional energy cost. The security of a Babylon-enhanced PoS protocol is formalized by a cryptoeconomic security theorem which shows slashable safety and liveness guarantees.