lightning network – Will LN liquidity advertisements and dual funding allow for third-party purchased liquidity (“sidecar channels”)?
Third-party purchased liquidity (“sidecar channels“) are a feature
of Lightning Pool where Alice pays Bob to fund a new channel to
Carol. Although this seems like an indirection (Alice could just use
her funds to open a channel to Carol directly) purchasing liquidity
through a third party eliminates Alice’s need to hold excess capital or
to run a well-connected node—she instead pays Bob for both the
temporary trustless use of his capital and the quality of his node’s
connections, allowing Carol to quickly and reliably begin receiving LN
payments through Bob’s node.
Liquidity advertisements based on dual funded channels are a
decentralized and fully open source alternative to the centralized
Lightning Pool marketplace (which has an open protocol but uses a
proprietary server). Although both protocols would allow Carol to buy
her own liquidity from Bob, only Lightning Pool advertises the ability
for third-party Alice to pay Bob for the liquidity he offers Carol.
Is third-party purchased liquidity also possible using liquidity
advertisements and dual funded channels?
It at least seems theoretically possible to me. The dual funding would
include an input from Alice paying Bob for his liquidity lease but the actual
multisig control over the channel funds would be between Bob and Carol.
However, it’s not clear to me how far this theory is from the reality of
what it would take to actually specify and implement that behavior.