Censorship isn't possible without surveillance, at the very least someone caring enough to act to censor when they observe something, and the only reason for surveillance is to control actions, which is censorship.  Of course, these can be used for "good", surveillance like security cameras that document who approaches your house, and censorship like parents controlling what their kids watch on television, but I'm not so sure that you can have one without the other.  If there is no censorship, there is no reason to survey, if there is no surveillance, attempts at censorship will be ineffective.