Timwi timwi@gmx.net wrote:
Eric wrote:
The aim is to identity each anonymous edit with a unique number. Right? Well then, a different unique number can be coded using a special formula which ends us up with a 1-to-1 relationship.
This means that the IP address can still be reconstructed from the "unique number". What you are suggesting is called "security by obscurity". Unfortunately, you are forgetting that the source code is open, and so any formula - no matter how complex - can be seen by everybody.
I've actually thought about this sort of thing for a site I've been planning with anonymous users. The trick is to assign a *meaningless* number that nonetheless consistently maps to a particular IP address.
CREATE TABLE anonips ( anonid INTEGER NOT NULL AUTO_INCREMENT PRIMARY KEY, ipaddr INTEGER NOT NULL );
Then add a Special:Anonip, limited to sysops, that looks up an anonymous user number in the table and returns the IP address.
Yes, if you happen to get the same IP as a previous user, you'll know their old IP address. But it doesn't have to be perfect.