#197: Joost Jager

— Griefing attacks on Lightning channels allow attackers to jam routing capacity by sending slow-settling payments at minimal cost, effectively disabling channels without stealing funds.

— Circuit Breaker is a mitigation tool that limits the number of in-flight HTLCs on incoming channels, raising the cost and complexity of executing channel jamming attacks.

— Multi-path payments and Wumbo channels together improve user experience and liquidity by allowing users to combine channel balances, potentially reducing the need for very large channels.

— Private vs. public channels: End users should primarily use private channels for non-routing purposes, while routing nodes benefit from private "shadow channels" to remain less visible as attack targets.

— Multiple Lightning implementations (LND, Eclair, C-Lightning) maintain interoperability through bi-weekly spec discussions, with each implementation exploring different technical approaches to features like MPP routing algorithms.

— Watchtowers and chain security remain important long-term concerns; watchtowers deter breach attempts through uncertainty, while fee market conditions and anchor channels help mitigate timelocked payment risks.

— If you operate a Lightning routing node, convert public Wumbo channels into private "shadow channels" and advertise only a single sufficiently-sized public channel to reduce your visibility as a jamming target while maintaining routing capacity.

— Limit incoming HTLCs on your channels via LND configuration flags (e.g., allowing only five HTLCs per peer) to increase the cost of griefing attacks; consider running Circuit Breaker for more granular controls.

— For end users not routing payments, create only private channels to trusted nodes (except for key-send payments, which may require a public channel until LN URL improvements mature).