A Taxonomy of Censors and Anti-Censors Part II: Anti-Censorship Technologies

2. Previous Research

Extant literature on circumvention technologies discusses several techniques and strategies for designing censorship resistant systems. There are two main dimensions: free access to information and free publication of information, the second being even more challenging than the first.

A key component for any censorship resistant system or circumvention technology is to ensure privacy by enabling users to communicate undetected in a censorship network. This is often accomplished by incorporating certain techniques such pseudonymity and anonymity into the system. However, previous research suggests that current techniques to ensure privacy still reveal a significant amount of identifying information (Rao & Rohatgi, 2000). Rao and Rohatgi (2000) indicate that techniques from linguistics and stylometry can use the identifying information to compromise pseudonymity. They suggest some countermeasures to address syntactic and semantic leaks of information. With respect syntactic leaks the authors suggest using a thesaurus tool, which could prompt the user to use alternatives while composing messages thereby reducing variations in vocabulary. For semantic leaks, they suggest translating the message to another language and then back again to the original language (Rao & Rohatgi, 2000).