This strikes me as a pretty difficult problem, since it touches on personal privacy, information security, and identification all at once...<p>The simplest solution would be a disassociated ID card with a 2 or 3 factor identification (eye scan, fingerprint, etc.). Except this requires everyone to register and isn&#x27;t going to gain widespread support in the U.S. for privacy reasons.<p>Info security just needs multiple factors, so require SSN and then an RSA-type second-factor to authenticate. This would make it about as secure as GMail, except for when you lose your PIN generator. I have backup codes for my GMail... How do we handle lost PINs when it&#x27;s personal ID at stake?<p>Identification could be as simple as a personal e-mail address... Except we have all kinds of things tied to SSN as ID, including credit history, bank loans, etc. that require proof of <i>individual</i> identity, not just &quot;unique identification&quot;.<p>Is this a solved problem?