HTLC endorsement
HTLC endorsement is a reputation system proposed for LN. When a node receives a payment (HTLC) from a channel counterparty for forwarding, that payment may be flagged as endorsed. If forwarded HTLCs from that counterparty have been profitable in the past, the node may choose to pass on that endorsement when it forwards the HTLC to the next hop.
Nodes opting into this endorsement protocol may give endorsed HTLCs access to more resources than unendorsed HTLCs. The two main resources would be access to a channel’s limited number of HTLC slots (the number of pending payments the channel can support) and the node’s liquidity (the amount of capital it has available in the channel). Both of those resources are vulnerable to being used without payment (or with insufficient payment) in a channel jamming attack.
With endorsement, someone executing a channel jamming attack that makes their counterparties less profitable will not have their HTLCs endorsed. Honest parties will continue to have their HTLCs endorsed and will be able to access any HTLC slots and liquidity that is only accessible to endorsed HTLCs.
Primary code and documentation
Optech newsletter and website mentions
2023
- HTLC endorsement testing and data collection
- LN developer discussion about channel jamming attacks and HTLC endorsement
- LND #7710 allows retrieving extra data about an HTLC in support of trying HTLC endorsement
- Eclair #2701 now records HTLC receive and settlement times to help later testing of HTLC endorsement
- Testing HTLC endorsement for preventing channel jamming attacks
- Feedback requested on HTLC endorsement to mitigate jamming
- Summary of call about mitigating LN jamming
2022
- 2022 year-in-review: HTLC endorsement for channel jamming
- Paper suggesting HTLC endorsement as part of a mitigation for jamming attacks
See also
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