Recipient Anonymity in a Structured Overlay

An open problem in structured overlay networks is related to the anonymity to be provided to recipients, namely, those nodes who respond to request messages. Such a feature is of main concerns when designing censorship-resistant distributed applications. In this paper it is shown that, in a chordal ring overlay, by enforcing a degree of imprecision in each peer’s routing table we obtain better recipient anonymity while keeping the length of routing paths within logarithmic length. A suitable metrics for recipient anonymity is established, based on the amount of resources an adversary needs in order to break anonymity of recipients in the overlay. In terms of this metrics, it is shown that imprecise routing tables make it impossible for a "small" coalition of malicious peers to correlate overlay addresses to hosts for censorship or auditing purposes.