Two Cents for Strong Anonymity: The Anonymous Post-office Protocol
We introduce the Anonymous Post-Office Protocol (AnonPoP), a practical strongly-anonymous messaging system. Its design effectively combines known techniques such as (synchronous) mix-cascade and constant sending rate, with several new techniques including request-pool, bad-server isolation and per-epoch mailboxes. AnonPoP offers strong anonymity against strong, globally-eavesdropping adversaries, that may also control multiple servers, including all-but-one servers in a mix-cascade. Significantly, AnonPoP’s anonymity holds even when clients may occasionally disconnect, which is essential for supporting mobile clients.