Actuarial System To Reduce Interactivity In N-of-N (N > 2) Multiparticipant Offchain Mechanisms

In this email, Antoine discusses the topic of ensuring lack of equivocation of an off-chain state. He suggests two possible approaches to achieve this. The first approach involves dynamically updating the subgroup of balance keys on-chain, using the blockchain as an anti-double spend oracle. The second approach involves designing a fraud-proof system that encumbers each channel factory or pool balance by leveraging OP_CHECKSIGFROMSTACK and the spent outpoint committed as a partial transaction template.

Antoine also mentions the concept of fidelity bonds in this context. He explains that the amount of satoshis (a unit of Bitcoin) locked in fidelity bonds should be equal to the counterparty's initial balance multiplied by the remaining counterparties. This is because one can cheat against every other party if there is no shared communication channel where equivocation can be observed. For example, if a factory has 1000 participants and a balance of 10,000 satoshis, they must lock up 10,000,000 in fidelity bonds while only 1/1000th of the amount can be leveraged as an off-chain contract or payment.

Antoine acknowledges that a pre-nominated coordinator can reduce the burden from the full fidelity bond. However, he also highlights the drawback of coordinator unavailability, where each participant would have to withdraw their balance on-chain and bear the fee cost.

Overall, Antoine's email discusses the options for ensuring lack of equivocation of an off-chain state, including dynamic updates on-chain and the use of fidelity bonds. He also considers the impact of a pre-nominated coordinator and the potential issues related to coordinator unavailability.