Here is a transaction graph that supports efficient collateral usage for operators:
- Operators provide signatures for the red arrows at the time of deposit.
- Every kickoff must be finalized before the operator sends the ready-to-reimburse transaction.
- A kickoff can get finalized with either challenge timeout transaction or disprove timeout transaction.
- Kickoffs can proceed in parallel, allowing many withdrawals to be processed with a single collateral.
- If one of the kickoffs is disproven, all reimbursements stop.
Current Limitations:
- A Bitcoin light client is needed to prove the inclusion of the payout transaction and the sidesystem’s state. (We are still working on this, but this also might add trust-minimized assumptions for safety)
- All operators’ signatures need to be published somewhere for data availability, and Bitcoin is not ideal for this due to limited block space.