Routing Payments on the Lightning Network

Bitcoin is a new digital currency created with the aim of being decentralized, peer-to-peer, censorship-resistant, borderless, scarce, fast and cheap to use. Since Bitcoin main way of operating is based on broadcast communications, e.g. all transactions of the currency reach all network peers, how to achieve scalability is one of the most important concerns for it to achieve wide usage. One of the proposals to improve its scalability takes the form of the Lightning Network (LN) which consists of an overlay network on top of the base Bitcoin layer. Such an overlay allows to perform a new kind of off-blockchain transactions, i.e. transactions not broadcast to the entire network, that, differently from previous off-blockchain solutions, do not require to put trust in any third entity. Important open problems of the LN are i) defining how payments should be routed and ii) establishing which fee policies intermediate nodes should apply for forwarding payments. The contributions of this work are twofold: we first propose a new, more general, way for nodes to apply fees for forwarding payments which allows to keep the network balanced and improve its performance in the long term. Secondly, we propose a new multipath routing payment scheme, based on the atomic multipath payment method, which is able to significantly reduce the fees paid by users, while being fast and also able to keep the network balanced.