Drivechain

Drivechain is a proposal to extend Bitcoin by allowing bitcoin to be moved onto separate blockchains, called sidechains, and later moved back, without relying on a custodian or a federation of trusted parties. Under the proposal, deposits into a sidechain would be locked on Bitcoin, and withdrawals back to Bitcoin would be approved by Bitcoin miners through a slow, public voting process. It was designed by the developer Paul Sztorc, who first described it in 2015, and is specified in two Bitcoin Improvement Proposals, BIP-300 and BIP-301.

Drivechain would require a soft fork, a backward-compatible change to Bitcoin's rules that needs broad support from users, node operators and miners. As of November 2026 neither BIP has been activated, and the proposal remains one of the most debated ideas in Bitcoin development. Its supporters see it as a way to add new features to Bitcoin without changing the main chain; its critics fear it would weaken Bitcoin's security model or change miners' incentives.

Bitcoin is deliberately conservative: changes are rare and slow, which keeps it stable but leaves out many features found on other blockchains. Drivechain would let people build extra blockchains alongside Bitcoin, each trying something different, such as more privacy, bigger blocks or smart contracts, while still using real bitcoin as their money.

Moving bitcoin onto one of these side roads is easy: the coins are locked in a special box on the main chain. Getting them back out is the tricky part. Under Drivechain, the people who secure Bitcoin, the miners, would vote over several months on each batch of withdrawals before the box could be opened. Anyone could watch the vote and object in public if something looked wrong.

Sztorc, who had earlier worked on a Bitcoin-based prediction-market design called Truthcoin, published the Drivechain idea in 2015 as a way to run such projects alongside Bitcoin rather than as separate coins. The two BIPs were drafted in 2017 and have been revised several times since, and test networks were run to demonstrate deposits, withdrawals and sample sidechains. Interest revived in 2023, when Sztorc's company released updated software and the proposals were debated again on developer mailing lists, at conferences and on social media. The debate became part of a wider discussion about how Bitcoin should add new capabilities, given that its last major soft fork, Taproot, activated in 2021.

• Hashrate escrows (BIP-300). Each sidechain would have an escrow on Bitcoin holding all the bitcoin deposited into it. To withdraw, the sidechain proposes a bundle of payments, and miners signal approval or rejection in the blocks they produce over a long voting window, roughly three months. Only bundles that reach a set level of support are paid out, a process that acts as a two-way peg between the chains.
• Blind merged mining (BIP-301). Sidechain blocks would be secured by Bitcoin miners, who could include sidechain block commitments in Bitcoin blocks and collect sidechain fees, without having to run sidechain software themselves.
• Sidechain freedom. Each sidechain could have its own rules and features, and failures or experiments there would not change the rules of the Bitcoin blockchain.

Supporters argue that Drivechain would let Bitcoin users access new features, such as privacy tools or prediction markets, without leaving bitcoin for other coins and without risky changes to the main chain. They say it could strengthen Bitcoin's long-term security by giving miners extra fee income as the block reward falls with each halving. They also argue that the long, visible withdrawal vote makes theft by miners slow, public and costly to their reputation and to the value of the coins they mine.

• Miner trust. Critics argue that sidechain users would ultimately depend on a majority of Bitcoin's hashrate acting honestly, a weaker guarantee than Bitcoin's own rules, and that a coalition of large mining pools could steal escrowed funds.
• Incentive changes. Some fear that rewards available on sidechains could encourage miners to extract value or to coordinate in ways that harm Bitcoin itself.
• Scope creep. Sidechains could host speculative tokens or applications that some Bitcoin users consider a distraction from Bitcoin's role as money.
• Activation risk. Opponents warn that pushing a contested soft fork could split the community.

Several other approaches aim to extend Bitcoin without Drivechain. The Lightning Network provides fast payments through channels secured by the main chain. Federated sidechains, such as Blockstream's Liquid, rely on a known group of functionaries to hold deposits. Projects like Stacks use their own tokens and consensus while anchoring to Bitcoin, and research such as BitVM explores verifying more complex computation using Bitcoin's existing rules. Drivechain's advocates continue to develop software and demonstration sidechains, and the proposal resurfaces in debates about which Bitcoin soft fork, if any, should come next. Any activation would depend on wide agreement across the Bitcoin community.

• BIP-300: Hashrate Escrows
• BIP-301: Blind Merged Mining