Drivechain
Also: BIP-300, BIP-301
lightning · advanced
A proposed Bitcoin soft fork letting users move BTC to sidechains secured by miners. Long-running, controversial, not deployed.
Drivechain is Paul Sztorc's design (2015, formalized as BIP-300/301) for sidechains that don't require a federation. Users lock BTC into a special output on the main chain; miners signal whether they've validated the sidechain; after a long timelock (months), users can withdraw based on miner signals. The mainchain itself doesn't validate sidechain rules.
The pitch: experiment with new features — better privacy, larger blocks, smart contracts — without forcing the changes onto Bitcoin's main chain. Coins always remain canonically Bitcoin; sidechains are opt-in escapes.
The critique: miner-signaled peg withdrawals concentrate trust in miners. A cartel could steal sidechain funds by misreporting state. Proponents argue the long withdrawal window and economic incentives make this irrational; critics argue it changes Bitcoin's security model from "validating nodes" to "miners with delay." The proposal has been debated since 2015 and remains uncategorized — neither activated nor formally rejected.