Towards Inferring Blockchain Overlay Topology through Network Tomography

Blockchains are typically managed by peer-to-peer (P2P) networks providing the support and substrate to the so-called distributed ledger (DLT), a replicated, shared, and synchronized data structure, geographically spread across multiple nodes. Despite many updates and studies in p2p network protocols, the most famous blockchains still make use of legacy mechanisms to maintain and manage their underlying network. For instance, the BTC blockchain and many others still make use of random connectivity, with each node connecting to a random subset of other nodes. The induced network topology might not only be very inefficient but might also cause high-security flaws. Unfortunately, the network topology of such systems is kept hidden to users for anonymity reasons. Still, there are many mechanisms that could allow one to gain non-negligible information on the network topology.

In this poster, we will present the techniques that we will put into practice to unveil famous blockchains underlying topology. Then, we will also present several outcomes of applying these techniques to blockchain networks. Particularly, we will present a use case with miners taking benefit of an unveiled topology to gain decision power within the system.