V3 transaction policy for anti-pinning

V3 transaction policy for anti-pinning

Original Postby t-bast

Posted on: February 9, 2024 09:59 UTC

The ongoing discussion about the appropriate value for the maximum number of pending Hashed Timelock Contracts (HTLCs) in commitment transactions on the network is complex due to a lack of widespread attack instances.

Historical data suggests that current attempts are generally honest, but there's no concrete evidence to determine a more optimal value. The potential size of a commitment transaction could become quite significant when filled with HTLCs. For instance, the Lightning Network Daemon (lnd) permits up to 483 HTLCs per direction within a commitment. Consequently, a fully populated commitment with twice this number would accumulate fees exceeding 800,000 satoshis at a rate of 20 sat/byte.

Given these considerations, it's recommended that node operators tailor their settings according to their individual circumstances, specifically aligning the max value and number of pending HTLCs they engage with to the on-chain fees they are prepared to pay. This personalization is crucial because default values tend to persist within the community and could place operators at risk if they do not incorporate some degree of flexibility to account for the variance in what different operators might consider too risky or too safe. However, determining an exact value that balances safety and risk effectively is challenging due to the diversity of needs and resources across operators.