Author: ZmnSCPxj 2020-01-27 15:10:24
Published on: 2020-01-27T15:10:24+00:00
In this email conversation, ZmnSCPxj discusses the AMCU paper which proposes a method for multi-channel updates with constant collateral in Bitcoin-compatible payment-channel networks. ZmnSCPxj explains that off-chain updateable cryptocurrency systems can host any contract that the hosting cryptocurrency system can host, including instances of itself.The base technique used by the AMCU paper is to realize that from a payment channel, it can instantiate two inner payment channels. Closing a sub-channel requires particular protocol rules to be followed, culminating in a transaction that spends the fund of the sub-channel to whatever set of contracts was agreed to be the latest channel state.One might consider that cryptocurrency systems basically allow the creation and destruction of UTXOs. In any case, from a skim of the AMCU paper, it looks like all the intermediate hops need to validate that all the other intermediate hops follow the protocol, by presenting all the transactions involved. This probably implies that all the intermediate hops know the entire route, and thus who the ultimate sender and receiver are, thus utterly bad for privacy.Subhra Mazumdar inquired about the possibility of locking a partial amount of funds in a payment channel instead of holding the entire channel fund when parties apply conditions for ensuring successful payments. In response, ZmnSCPxj clarified that for a payment less than the channel funds on one side, only the amount required for payment transfer is locked behind an HTLC and the remaining amount remains usable for other HTLCs.The concept of subchannels in a single channel has been suggested in "Atomic multi-channel updates with constant collateral in bitcoin-compatible payment-channel networks." However, Subhra still had doubts about what happens during the closing of subchannels.
Updated on: 2023-06-02T22:49:31.241429+00:00