Decoy Routing: Toward Unblockable Internet Communication Josh Karlin Daniel Ellard Alden W. Jackson Christine E. Jones
[email protected] [email protected] [email protected] [email protected] Greg Lauer David P. Mankins W. Timothy Strayer
[email protected] [email protected] [email protected] Raytheon BBN Technologies an indirect method, such as a proxy server placed out- side of the filtered network. At a high level, this is the Abstract mechanism used by popular services such as Tor [13], Global Pass [4], and anonymizer.com [2]. Clients con- We present decoy routing, a mechanism capable of cir- nect to a server located outside of the filtered network, cumventing common network filtering strategies. Unlike and the server connects to the blacklisted destination on other circumvention techniques, decoy routing does not the client’s behalf. Although these services use differ- require a client to connect to a specific IP address (which ent techniques (VPNs, SOCKS proxies, HTTP proxies, is easily blocked) in order to provide circumvention. We content forwarders) we categorize them collectively as a show that if it is possible for a client to connect to any circumvention proxy or proxy. unblocked host/service, then decoy routing could be used to connect them to a blocked destination without coop- The problem with the proxy approach to circumven- eration from the host. This is accomplished by placing tion is that the adversary can also blacklist the circum- the circumvention service in the network itself – where vention proxy, preventing communication between the a single device could proxy traffic between a significant client and the proxy.