Anonymity Assessment and Protection

MOTIVATION

Public interest in anonymous communication systems has vastly increased in recent years, with the Tor network being the most prominent example, currently serving millions of users from all over the world. Rigorously assessing the degree of anonymity provided by Tor as well as developing alternative anonymous communication networks are central research directions in this problem space.

CURRENT RESEARCH LINES

Anonymity Assessment for Tor. Previous works on assessing the degree of anonymity in Tor were either purely empirical, or they abstracted from Tor’s central real-world characteristics such as the path selection algorithm, the Tor consensus data, and the users’ preference ports. To overcome this shortcoming, we research frameworks for rigorously and quantitatively assessing the degree of anonymity for Tor end users in real time depending on different trust assumptions, while taking all these real-world characteristics into account.

Anonymity Protection. Existing anonymous communication protocols struggle to simultaneously achieve strong anonymity guarantees, low latency, and protection against slot collisions and malicious peers. We research mixing protocols that overcome this limitation. Our innovations can serve as an ideal privacy-enhancing extension to cryptocurrencies and credit networks, as it enables unlinkability of transactions for pseudonymous users, while offering seamless integration into existing systems. Our work provides the provably secure, privacy-preserving payment protocol for credit networks that offers full obliviousness of transactions, while simultaneously entailing strong privacy guarantees for payments.