347 sats \ 5 replies \ @softsimon 15 Sep 2022 \ on: I'm Tony Giorgio, Lightning Developer and Researcher. AMA. bitcoin
Lightning Privacy: When I make a LN payment. Who/what can see I made the payment? Who can see and know from which UTXOs the payment come from? How is the privacy different depending if I am the sender or the receiver?
The hand wavy answer with Lightning is supposed to provide enough anonymity on the sender side through the onion routing aspects, but there's tons of nuances there. Absolutely worst case scenario, the actors routing the payment know that it was you that sent it and the destination (very common in single/double hop scenarios and especially with LSPs - some LSPs like Muun or Phoenix would know everything about the payments you make).
Some of the recent protocol changes fix some of the issues regarding UTXO's in unannounced channels (that my project https://bitcoindevshop.github.io/hidden-lightning-network/ highlights). But otherwise, your channel partner will always know the UTXO that is used to fund the channel.
Receivers have almost no privacy currently on LN, while in general scenarios, senders have pretty good privacy. If you're paying just a normal person on LN that's not a direct channel partner (if you have other public channels), there's pretty good assurances they won't know who it came from. It's just that it gets tricky with LSPs or bad actors.
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Very good question with a very good answer. Thanks!
Tony, do you think Anton's (SBW wallet) private routing proposal could help in some way if could be introduced/adapted in more LN implementations?
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I have not looked at in awhile. Is that the same or similar to Immortan? If it works like the way I assume it could work, I was always a fan of it in concept. I am not sure how difficult it is to accomplish on the UX side, and I believe you're seeking privacy behind a third party, which is an improvement than everyone knowing when you're also wanting to be a routing node. But in general, I like the concept of non-custodial "community nodes" which is probably not marketed that way but in my head that's the way I have thought about the problem I think they are trying to solve.
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Yes, private routing is part of Immortan implementation. Some kind of trampoline channels. Definitely worth looking into.
Maybe @fiatjaf could help with more insight here.
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It was never released. The code is there but I am not sure if it works and the details are nebulous to me. If you happen to be near Ukraine you could go ask Anton.
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