On the Trade-off between Relationship Anonymity and Communication Overhead in Anonymity Networks

Abstract—Motivated by protection and privacy in industrial communication networks, in this paper we consider the tradeoff between relationship anonymity and communication overhead. We consider two anonymity networks: Crowds, which has unbounded communication delay and Minstrels, proposed in this paper, which provides bounded communication delay. While Crowds hides the sender’s identity only, Minstrels aims at hiding the receiver’s identity as well. However, to achieve bounded communication delay it has to expose the sender’s identity to a greater extent than Crowds. We derive exact and approximate analytical expressions for the relationship anonymity for these systems. While Minstrels achieves close to optimal anonymity under certain conditions, our results show that, contrary to expectations, increased overhead does not always improve anonymity. I