bLIP-56: Pluggable Channel Factories.

[ZmnSCPxj-jr]

Channel factories are a way of scaling Bitcoin by hosting offchain channels, not directly onchain, but in another offchain mechanism. The hosting mechanism is called a channel factory. The channel factory can change the funding amounts of channels inside the factory, without any onchain transactions.

This pluggable channel factory protocol is a proposal by which base node software can handle channel state, while letting external code handle state of the channel factory. As far as the node software is concerned, the channel is a "0-conf" channel whose funding transaction never seems to confirm, even though the state is actually backed by an offchain mechanism that ensures that the channel can be unilaterally closed in the worst-case scenario.

When the channel factory wants to change the funding amounts of hosted channels, the node software acts as if a splice operation is being performed, which changes the funding amount (or not changes it, if it is other channels in the same factory that are changed but not this one). When the channel factory offchain mechanism has settled to a new state, it is as if a splice transaction was successfully deeply confirmed.