The growing ecosystem of blockchain systems built around Bitcoin has created a pressing need for secure and efficient bridges to transfer BTC between networks while preserving Bitcoin's security guarantees.

The Union bridge is the first capital-efficient permissionless security-bonded bridge that can extend to hundreds of participants resting on a single honest verifier.

Union employs a multi-party variant of BitVMX, an optimistic proving system on Bitcoin, to create a bridge that operates securely under the assumption that at least one participant remains honest.

Access Union Bridge whitepaper here.