Reusable anonymous return channels

Mix networks are used to deliver messages anonymously to recipients, but do not straightforwardly allow the recipient of an anonymous message to reply to its sender. Yet the ability to reply one or more times, and to further reply to replies, is essential to a complete anonymous conversation. We propose a protocol that allows a sender of anonymous messages to establish a reusable anonymous return channel. This channel enables any recipient of one of these anonymous messages to send back one or more anonymous replies. Recipients who reply to different messages can not test whether two return channels are the same, and therefore can not learn whether they are replying to the same person. Yet the fact that multiple recipients may send multiple replies through the same return channel helps defend against the counting attacks that defeated earlier proposals for return channels. In these attacks, an adversary traces the origin of a message by sending a specific number of replies and obser...

• Type: Conference
• Year: 2003
• Where: WPES
• Authors: Philippe Golle, Markus Jakobsson
• Keywords: Anonymous Messages, Mix Networks, Return Channel, WPES 2003