  Bitcoin's Lightning Network (LN) is a scalability solution for Bitcoin
allowing transactions to be issued with negligible fees and settled instantly
at scale. In order to use LN, funds need to be locked in payment channels on
the Bitcoin blockchain (Layer-1) for subsequent use in LN (Layer-2). LN is
comprised of many payment channels forming a payment channel network. LN's
promise is that relatively few payment channels already enable anyone to
efficiently, securely and privately route payments across the whole network. In
this paper, we quantify the structural properties of LN and argue that LN's
current topological properties can be ameliorated in order to improve the
security of LN, enabling it to reach its true potential.
