{"type":"rich","version":"1.0","author_name":"npub1wtx5qvewc7pd6znlvwktq03mdld05mv3h5dkzfwd3dc30gdmsptsugtuyn","author_url":"https://nostr.ae/npub1wtx5qvewc7pd6znlvwktq03mdld05mv3h5dkzfwd3dc30gdmsptsugtuyn","provider_name":"njump","provider_url":"https://nostr.ae","html":"📅 Original date posted:2023-05-10\n🗒️ Summary of this message: Reputation systems in Lightning Network are susceptible to sudden behavioral changes and whitewashing attacks, making them less useful. Local-only reputation systems may work for large routing nodes, but edges are more vulnerable.\n📝 Original message:\nHi Antoine,\n\nthis is an intrinsic issue with reputation systems, and the main\nreason I'm sceptical w.r.t. their usefulness in lightning.\nFundamentally any reputation system bases their expectations for the\nfuture on experiences they made in the past, and they are thus always\nsusceptible to sudden behavioral changes (going rogue from a prior\nclean record) and whitewashing attacks (switching identity, abusing\nany builtin bootstrapping method for new users to gain a good or\nneutral reputation before turning rogue repeatedly).\n\nThis gets compounded as soon as we start gossiping about reputations,\nsince now our decisions are no longer based just on information we can\nwitness ourselves, or at least verify its correctness, and as such an\nattacker can most likely \"earn\" a positive reputation in some other\npart of the world, and then turn around and attack the nodes that\ntrusted the reputation shared from those other parts.\n\nI'd be very interested in how many repeat interactions nodes get from\nindividual senders, since that also tells us how much use we can get\nout of local-only reputation based systems, and I wouldn't be\nsurprised if, for large routing nodes, we have sufficient data for\nthem to make an informed decision, while the edges may be more\nvulnerable, but they'd also be used by way fewer senders, and the\nimpact of an attack would also be proportionally smaller.\n\nCheers,\nChristian\n\nOn Mon, May 8, 2023 at 10:26 PM Antoine Riard \u003cantoine.riard at gmail.com\u003e wrote:\n\u003e\n\u003e Hi *,\n\u003e\n\u003e \u003e Our suggestion is to start simple with a binary endorsement field. As\n\u003e \u003e we learn more, we will be better equipped to understand whether a\n\u003e \u003e more expressive value is required.\n\u003e\n\u003e I think the HTLC endorsement scheme as proposed is still suffering from a vulnerability as local reputation can be built up during periods of low routing fees, endorsement gained and then abused during periods of high routing fees. Therefore, it sounds to me this scheme should aim for some reputational transitivity between incoming traffic and outgoing traffic. Namely, the acquisition cost of the local reputation should be equal to the max timevalue damage that one can inflict on a routing node channel accessible from its local counterparty granting this high-level of reputation.\n\u003e\n\u003e I don't know if this can be fixed by ensuring permanent link-level \"gossip\" where counterparties along a payment path expose their reputation heuristics to guarantee this transitivity, or it's a fundamental issue with a point-to-point approach like HTLC endorsement.\n\u003e\n\u003e Opened an issue on the repository to converge on a threat model:\n\u003e https://github.com/ClaraShk/LNJamming/pull/13\n\u003e\n\u003e I still think building data gathering infrastructure for Lightning is valuable as ultimately any jamming mitigation will have to adapt its upfront fees or reputation acquisition cost in function of HTLC traffic and market forces.\n\u003e\n\u003e Looking forward to giving an update on Staking Credentials [0], an end-to-end approach to mitigate channel jamming.\n\u003e\n\u003e Best,\n\u003e Antoine\n\u003e\n\u003e [0] https://lists.linuxfoundation.org/pipermail/lightning-dev/2022-November/003754.html\n\u003e\n\u003e Le dim. 30 avr. 2023 à 03:57, Carla Kirk-Cohen \u003ckirkcohenc at gmail.com\u003e a écrit :\n\u003e\u003e\n\u003e\u003e Hi list,\n\u003e\u003e\n\u003e\u003e Some updates on channel jamming!\n\u003e\u003e\n\u003e\u003e # Next Call\n\u003e\u003e - Monday 01 May @ 15:00 UTC\n\u003e\u003e - https://meet.jit.si/UnjammingLN\n\u003e\u003e - Agenda: https://github.com/ClaraShk/LNJamming/issues/12\n\u003e\u003e\n\u003e\u003e # Data Gathering\n\u003e\u003e During these weekly calls, we've come to agreement that we would like\n\u003e\u003e to gather data about the use of HTLC endorsement and local reputation\n\u003e\u003e tracking for jamming mitigation. A reminder of the full scheme is\n\u003e\u003e included at the end of this email, and covered more verbosely in [1].\n\u003e\u003e\n\u003e\u003e We have a few goals in mind:\n\u003e\u003e - Observe the effect of endorsement in the steady state with\n\u003e\u003e   logging-only implementation.\n\u003e\u003e - Gather real-world data for use in future simulation work.\n\u003e\u003e - Experiment with different algorithms for tracking local reputation.\n\u003e\u003e\n\u003e\u003e The minimal changes required to add HTLC endorsement are outlined in [2].\n\u003e\u003e Our suggestion is to start simple with a binary endorsement field. As\n\u003e\u003e we learn more, we will be better equipped to understand whether a\n\u003e\u003e more expressive value is required.\n\u003e\u003e\n\u003e\u003e With this infrastructure in place, we can start to experiment with\n\u003e\u003e various local reputation schemes and data gathering, possibly even\n\u003e\u003e externally to LN implementations in projects like circuitbreaker [3].\n\u003e\u003e We'd be interested to hear whether there's any appetite to deploy using\n\u003e\u003e an experimental TLV value?\n\u003e\u003e\n\u003e\u003e # Reputation Scheme\n\u003e\u003e - Each node locally tracks the reputation of its direct neighbors.\n\u003e\u003e - Each node allocates, per its risk tolerance:\n\u003e\u003e   - A number of slots reserved for endorsed HTLCs from high reputation\n\u003e\u003e     peers.\n\u003e\u003e   - A portion of liquidity reserved for endorsed HTLCs from high\n\u003e\u003e     reputation peers.\n\u003e\u003e - Forwarding of HTLCs:\n\u003e\u003e   - If a HTLC is endorsed by a high reputation peer, it is forwarded\n\u003e\u003e     as usual with endorsed = 1.\n\u003e\u003e   - Otherwise, it is forwarded with endorsed = 0 if there are slots and\n\u003e\u003e     liquidity available for unknown HTLCs.\n\u003e\u003e\n\u003e\u003e Endorsement and reputation are proposed as the first step in a two part\n\u003e\u003e scheme for mitigating channel jamming:\n\u003e\u003e - Reputation for slow jams which are easily detected as misbehavior.\n\u003e\u003e - Unconditional fees for quick jams that are difficult to detect, as\n\u003e\u003e   they can always fall under a target threshold.\n\u003e\u003e\n\u003e\u003e Looking forward to discussing further in the upcoming call!\n\u003e\u003e\n\u003e\u003e Best,\n\u003e\u003e Carla and Clara\n\u003e\u003e\n\u003e\u003e [1] https://gist.github.com/carlaKC/be820bb638624253f3ae7b39dbd0e343\n\u003e\u003e [2] https://github.com/lightning/bolts/pull/1071\n\u003e\u003e [3] https://github.com/lightningequipment/circuitbreaker\n\u003e\u003e _______________________________________________\n\u003e\u003e Lightning-dev mailing list\n\u003e\u003e Lightning-dev at lists.linuxfoundation.org\n\u003e\u003e https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev\n\u003e\n\u003e _______________________________________________\n\u003e Lightning-dev mailing list\n\u003e Lightning-dev at lists.linuxfoundation.org\n\u003e https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev"}