HushRelay: A Privacy-Preserving, Efficient, and Scalable Routing Algorithm for Off-Chain Payments

Payment channel networks (PCN) are used in cryptocurrencies to enhance the performance and scalability of off-chain transactions. Except for opening and closing of a payment channel, no other transaction requests accepted by a PCN are recorded in the Blockchain. In practical scenario, it may not be possible to transfer high valued payment across a single path. For such cases, splitting up the transaction value across multiple paths is a better approach. While there exists several approaches which route transactions via several paths, such techniques are quite inefficient, as the decision on the number of splits must be taken at the initial phase of the routing algorithm [39]. Such decisions are made by not taking into account the residual capacity of each channel in the network. Other approaches leak sensitive information, and are quite computationally expensive [26]. To the best of our knowledge, our proposed scheme HushRelay is an efficient privacy preserving routing algorithm, solving the problems encountered in existing works. On comparing the performance of our algorithm with existing routing scheme SpeedyMurmur [39] on real instances, we observed that HushRelay attains a higher success ratio with less execution time.