Bitcoin Magazine Podcast
Jeremy Rubin on Char: The Infrastructure Bet Underneath Every Bitcoin L2
- Char is a layer two consensus mechanism for rollups that decentralizes sequencing, a function currently controlled by single operators or small committees in most layer two projects.
- The protocol uses proof of stake built on Bitcoin, where stakers risk their locked Bitcoin as collateral; equivocation (signing conflicting messages) results in slashing, creating economic disincentives without requiring proof-of-work.
- Char recently implemented EVRF (exponent verifiable random function) via the Purify primitive (from Blockstream's MuSigDN paper), which dramatically simplified signature attestation and context tracking in the protocol.
- The staking mechanism works through anchor outputs and lock-timed outputs on-chain; enforcement of slashing is probabilistic and miner-dependent, relying on miners' incentive to sweep funds from misbehaving stakers.
- Char avoids trust assumptions down the stack by using Bitcoin's existing primitives rather than introducing new cryptographic assumptions.
- The broader vision is to support high-throughput, decentralized layer two settlement for Bitcoin without sacrificing security to a single trusted operator.