Inspecting the despicable, assessing the unacceptable: Prohibited packets and the Great Firewall of Canberra

At first glance the Australian Government's 2008 proposal to install a two-layered mandatory Internet 'content filtering' regime at ISP level - rather than the current opt-in filtering at the user's personal computer - appears relatively straightforward, with a clear mandate, solid unobjectionable aims, little change from existing legal principles and governance frameworks, and challenging but achievable technical goals. Closer inspection does not sustain this appearance; each of these conclusions is shaky; and there are as many interpretations of what is really at stake as there are observers. This paper explores some of the issues that complicate policy development and technical assessment.