(Oops, forgot to include 'punks, sorry Nick) Nick Szabo asks:
Is a one-way hash function or digital signature possible with the following property: signature verification doesn't just determine the boolean altered vs. pristine, but also shows the picture distance between the altered and original?
This is possible. It is not a desirable quality for secure-hashes in most other situations because it compromises the privacy of the original message. Hash functions are usually designed specifically to avoid this. Scott Collins | "Few people realize what tremendous power there | is in one of these things." -- Willy Wonka ......................|................................................ BUSINESS. voice:408.862.0540 fax:974.6094 collins@newton.apple.com Apple Computer, Inc. 5 Infinite Loop, MS 305-2B Cupertino, CA 95014 ....................................................................... PERSONAL. voice/fax:408.257.1746 1024:669687 catalyst@netcom.com