From ZmnSCPxj at protonmail.com Mon Nov 2 23:10:39 2020 From: ZmnSCPxj at protonmail.com (ZmnSCPxj) Date: Mon, 02 Nov 2020 23:10:39 +0000 Subject: [Lightning-dev] Hold fees: 402 Payment Required for Lightning itself In-Reply-To: References: Message-ID: Good morning t-bast, > > An issue with the bidirectional upfront/hold fees is related to trustless offchain-to-onchain swaps, like Boltz and Lightning Loop. > > As the claiming of the offchain side is dependent on claiming of the onchain side of the trustless swap mechanism, which is *definitely* slow, the swap service will in general be forced to pay up the hold fees. > > Yes, that is a good observation. > But shouldn't the swap service take that into account in the fee it collects to > perform the swap? That way it is in fact the user who pays for that fee. The user can wait for the swap service to put an onchain HTLC and then time it out. Thus, the offchain/onchain swap service will pay for both the onchain HTLC and the hold fee. This is fixed in e.g. Boltz by having a separate mining-fee invoice as well that must be paid before the offchain/onchain swap service will create the onchain HTLC. This is why I thought it would be better to include the hold fee in the mining-fee invoice as well. Regards, ZmnSCPxj