Lightning Network – Knowing the LN intermediate nodes for a transaction?

The intermediate nodes know the ID of the previous hop and the ID of the next hop, as well as the forwarded amount, hash lock, and timeout values. Typically, the forwarder does not know the identity of the sender and recipient.

Forwarding requests are always padded to the same size, so the forwarder does not know how many hops it leads or succeeds. Using information about the topology, the forwarder can make an informed guess if the origin and destination are the first or last hop and can assume that neighbors are not participating in the forwarding (e.g. because there are no (other) public hops). A mobile client that only accesses a channel or is intermittently online. I’m not sure, as other nodes may have additional private channels.

Two colluding forwarders can easily identify that all Hash Time Locked Contracts (HTLCs) along the route are part of the same payment because they use the same hash to set up their forwarding contracts.

Work is underway to replace HTLC with Point Time Locked Contract (PTLC) based on Schnorr signatures. In payments using PTLC, each hop has its own secrets that make it difficult to link forwarding activities, but even so, the amount, timeout value, and timing of the forwarding request may be enough to infer that separate hops belong to the same payment. . Combining PTLC with multi-path payments makes connecting different payment hops more difficult.