Typically security involves three things: * Something you have (like an access card or badge) * Something you know (like a password) * Something you are (lik

Typically security involves three things: * Something you have (like an access card or badge) * Something you know (like a password) * Something you are (like a fingerprint, iris scan, or a simply a photo) Fingerprints are bit weird as you do in fact leave them around everywhere. Like iris scans I would qualify them as better photographs.