This paper, presented at the Financial Cryptography and Data Security 2024 conference, offers an analytical approach to mitigating possible DoS risks associated with OM. Available for review at https://fc24.ifca.ai/preproceedings/104.pdf, it addresses the technical nuances and proposes several countermeasures to enhance network resilience.

An interesting point raised in the paper is the recalibration of the maximum number of hops an OM can make, which was previously set based on outdated payload size assumptions. With the transition to a new format where the per hop payload size is 68 bytes, the maximum traversable hops have been adjusted down from 504 to 481. This adjustment underscores the evolving nature of the Lightning Network's structure and the need for continuous analysis to keep security measures up to date.

Among the mitigation strategies proposed, the introduction of a "Soft Leash" mechanism stands out. It mandates a proof-of-work (PoW) for each additional hop an OM intends to traverse, exponentially increasing the computational effort required as more hops are added. This approach borrows from defenses used by Tor to prevent abuse of its services, as detailed in Tor's blog post. By tying the difficulty of sending OMs to computational work, the proposal aims to deter malicious actors from exploiting the system for DoS attacks.

Furthermore, the paper suggests implementing rate limiting based on the total channel capacity of the receiving node, ensuring that the flow of outgoing OMs remains proportional to the network's ability to handle them. This would prevent nodes from being overwhelmed by excessive traffic, maintaining stability and service availability. Another recommendation involves adjusting routing protocols to prioritize paths with higher cumulative channel capacities, thereby leveraging the network's most capable nodes for message transmission. Such a measure not only aims to optimize routing efficiency but also to render potential attacks less feasible financially and technically.

Overall, the research by Bashiri and Khabbazian provides valuable insights into securing the Lightning Network against DoS threats through strategic limitations on OM handling. Their work highlights the importance of adapting security measures to match the network's evolving architecture and the sophisticated nature of potential threats, contributing significantly to the ongoing dialogue on Lightning Network security enhancements.