[ptorr] Why not use hashes for the Anti-Phishing Filter? Several people have asked why Internet Explorer 7 will send "real" URLs instead of hashes to the AP (Anti-Phishing) server. That's a good question, and I know it's a good question because it's the same thing just about everybody at Microsoft (including me) says the first time they hear about the feature :-). Nevertheless, a fairly quick investigation into the issue shows that it buys very little in terms of privacy but comes at significant cost. First we need to figure out what threats are mitigated by sending hashes instead of URLs. Next we need to figure out what additional threats surface if we send hashes instead of URLs. Finally we determine which is "better" using some subjective measurement.

http://blogs.msdn.com/ptorr/archive/2005/09/13/464376.aspx

A very good article and reference about the new anti-fishing server feature of IE7!

Urs