  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. Only the parties which have opened the channel
will know the exact amount of fund left at a given instant. In real scenarios,
there might not exist a single path which can enable transfer of high value
payments. 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 (e.g., SpeedyMurmur [42]). Algorithms which do not consider
the residual capacity of each channel in the network are susceptible to
failure. Other approaches leak sensitive information, and are quite
computationally expensive [28]. To the best of our knowledge, our proposed
scheme HushRelay is an efficient privacy preserving routing algorithm, taking
into account the funds left in each channel, while splitting the transaction
value across several paths. Comparing the performance of our algorithm with
existing routing schemes on real instances (e.g., Ripple Network), we observed
that HushRelay attains a success ratio of 1, with an execution time of 2.4 sec.
However, SpeedyMurmur [42] attains a success ratio of 0.98 and takes 4.74 sec
when the number of landmarks is 6. On testing our proposed routing algorithm on
the Lightning Network, a success ratio of 0.99 is observed, having an execution
time of 0.15 sec, which is 12 times smaller than the time taken by
SpeedyMurmur.
