Labeling Usenet articles.

OK, so I want to enable the recieving of articles in conjunction with a censorship service. I guess the way to do this is a sig. of the article number, as this is the most copact way I can think of. Does anyone have some good ideas for the sig. method? I was thinking about the government one, so as to render patents moot. The other problem is coming up with a standard format so that newsreaders(for unix, at least 6, for dos, mac, etc) can be easily modified. Anyone have some interest in this? Lets get the tools of crypto out there in advance. Berzerk.