The Lightning Network Whitepaper describes the concept of Revocable Sequence Maturity Contracts (RSMC), which allows a commitment transaction to be revoked during a predefined delay after the channel gets closed unilaterally. As I understand, this means the channel closer (aka the node who published the transaction) must wait for the delay before claiming his/her invested money and, in the meantime, the counterparty can verify the blockchain to see if the closer published the most recent commitment transaction. If the closer published an old transaction, the counterparty can punish him/her by taking all the money in the channel. BOLT#3 defines this delay as the
to_self_delay variable in a commitment transaction output. However, some aspects about the RSMC implementation remain unclear to me:
- Who defines
to_self_delay? How does the LN ensure the delay is enough for the counterparty to punish a malicious user?
- Can the delay change for each commitment transaction? E.g. can two parties decide to decrease the delay if they trust each other more after some transactions?
Thanks in advance.