Drivechains and Spacechains Two proposed sidechain mechanisms for Bitcoin. Neither is active on mainnet . Drivechains (BIP300/301) Proposed by Paul Sztorc. BIP300: Hashrate Escrow - New tx types for "deposits" and "withdrawals" between Bitcoin and a sidechain. - Withdrawals require miner approval via signaling over a multi-block window. - Funds locked in a special multisig that miners can release based on the signaling. BIP301: Blind Merge Mining - Miners merge-mine sidechain blocks via Bitcoin coinbase commitments. - No additional hashpower required. - Blind: miners need not run the sidechai…