X9.84 biometric standard & some other work means that you could actually record all ten fingers in the card and any one would be acceptable. I believe just plain dirty fingers are much more of a problem than a cut. Simple cut can be "read-around" ... massive cut affecting the whole finger is problem. .... unless you are talking about blood contamination if band-aid is involved which would have to be removed.
What happens when a person forgets their pin (password) (one of the most common customer call center calls ... and represents a significant percentage of total customer call center costs when pin/password support is involved)? One of the reasons that suprising percentage of cards have PINs written on them (and postits with passwords are found near PCs). What happens when person doesn't have any fingers? You can still support pin-pad in parallel ... assuming that pin-pad is acceptable to people w/o any fingers. Next level gets somewhat more expensive ... having pin-pad, finger reader, and say iris scan (recording all ten fingers and both iris (lots of work that not only are all iris unique, even identical twins ... but left & right in same person are unique, iris is also possible in most blind people), plus finger-length scan. And what happens when I am unable to press my thumb against the reader because it is bandaged; or when my thumb ID fails because it was sliced with a knife. --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]