Evaluation of the anonymous I2P network's design choices against performance and security

Anonymous communications are growing extremely fast because more and more Internet users employ anony mous systems, such as the I2P or Tor networks, as a way to hide their online activity. Therefore, these networks have been more and more studied, mainly from a security point of view. Different studies have shown important design flaws in these systems that could break users' anonymity and how these issues can be overcome, but the resilience of the underlying information systems has not been much investigated so far. Indeed, these anonymous systems rely entirely on directories, either centralised or decentralised, to store vital network information. In this paper, we consider the I2P anonymous system and its decentralised directory, known as the netDB, where our contributions are twofold. On the one hand, we conduct arguably the first churn study of the I2P network, showing that I2P users are more stable than non-anonymous peer-to-peer users. On the other hand, we analyse the design of the netDB and compare it against the popular KAD design, demonstrating that the former is more vulnerable to different attacks, specially to Eclipse attacks, which can be mitigated by applying design choices of the latter. We lately show the positive impact on performances of including KAD's DHT configuration into the netDB in terms of bandwidth, storage and messages overhead.