Visible to the public Anonymity Trilemma: Strong Anonymity, Low Bandwidth Overhead, Low Latency - Choose Two

TitleAnonymity Trilemma: Strong Anonymity, Low Bandwidth Overhead, Low Latency - Choose Two
Publication TypeConference Paper
Year of Publication2018
AuthorsDas, D., Meiser, S., Mohammadi, E., Kate, A.
Conference Name2018 IEEE Symposium on Security and Privacy (SP)
KeywordsAC protocol nodes, AC protocols, AC systems, anonymity, anonymity trilemma, anonymous communication protocols, Bandwidth, bandwidth overhead, composability, cryptography, fundamental constraints, Human Behavior, human factors, latency overhead choices, low bandwidth overhead, low latency overhead, Metrics, nontraditional bandwidth, Petri nets, privacy, Protocols, pubcrawl, recipient anonymity, resilience, Resiliency, sender anonymity, strong anonymity, Synchronization, telecommunication security, trilemma

This work investigates the fundamental constraints of anonymous communication (AC) protocols. We analyze the relationship between bandwidth overhead, latency overhead, and sender anonymity or recipient anonymity against the global passive (network-level) adversary. We confirm the trilemma that an AC protocol can only achieve two out of the following three properties: strong anonymity (i.e., anonymity up to a negligible chance), low bandwidth overhead, and low latency overhead. We further study anonymity against a stronger global passive adversary that can additionally passively compromise some of the AC protocol nodes. For a given number of compromised nodes, we derive necessary constraints between bandwidth and latency overhead whose violation make it impossible for an AC protocol to achieve strong anonymity. We analyze prominent AC protocols from the literature and depict to which extent those satisfy our necessary constraints. Our fundamental necessary constraints offer a guideline not only for improving existing AC systems but also for designing novel AC protocols with non-traditional bandwidth and latency overhead choices.

Citation KeydasAnonymityTrilemmaStrong2018