The Free Haven design requires a means of anonymously passing information between agents. One such means is the remailer network, including the Mixmaster remailers first designed by Lance Cottrell [16]. Other examples of anonymous communication channels are Onion Routing [42] and Zero Knowledge Systems' Freedom [17]. We refer to David Martin's thesis for a comprehensive overview of anonymous channels in theory and practice [28].
The design and implementation of an anonymous communication channel is an ongoing research topic [1,5,7,8,20,21,22,24,33,36]. The first implementation of the Free Haven design will use the Cypherpunk and Mixmaster remailers as its anonymous channel. For design details, see [15].