digital id : Java Glossary


digital id
One type of digital id works on the principles of public key cryptography. Only you know a private key. It lives hidden inside your smart card or a fob in a way that makes it very difficult to get it out. Attempts to do so destroy the card. Your corresponding public key is on file as a matter of public record. To prove you are you to a merchant, the merchant gives your smart card a challenge phrase to encrypt. The card does so using its private key and a tiny embedded Java engine. The merchant then decrypts the result with your public key. If it gets back where it started, it proves your card contains the secret private key. The card never reveals the key itself.

Information embedded electronically in the card, such as name, address, account number, phone number, id number and public key can be digitally signed by some authority, in a way that it is tamper proof. This way, it in not necessary to check with some central database when checking the card.

Air port authorities would still need to check a database to discover recent no-fly restrictions.

Of course, it does not prove that the person holding the card is you, just that the card itself is not a forgery.

Other schemes examine thumbprints, or retinal patterns or signatures and compare them the ones on file. The problem is when you measure, you never get exactly the same numbers, so the matching has to be approximate.

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