Comparative remailer mix neworks, onion routing and pEp

This is not an exhautive comparative and might not be accurate.

It is base on the pages:

  Remailer Mixnetwor ks   Onion Routing pEp MixMailer
  Type I/Cypherp unks Type II/Mixmas ter Type III/Mixmi nion Tor  
transport SMTP SMTP TLS + SMTP? TLS SMTP?
nodes key NA yes yes yes yes (OpenPGP) ?
key rotation NA no yes yes active/pa sive
nodes/key discovery manual pinger? directory dirauths GNS?
types of nodes NA same? several? “G,M,E” same?
packet format ? ? Sphinx specific ?
packet size different same? same same different in future?
packet mixing NA yes yes no yes in future?
cover traffic NA yes yes? no ?
directory server no no central decentral ized GNS/trust ed nodes?
reply no no SURB “yes, circuit” NA
spam yes yes yes NA ?
network diversity no no no yes ?
user friendly no no no yes ?
old crypto yes yes yes no ?