Expiry

Full Title or Meme

Certificates and Credentials typically include an Expiry date-time or event, such as "on first use".

Context

• Many digital documents include a start data and an Expiry date.
• Many digital documents include a nonce or serial number which typically is used to ensure that the document is only processed on time, and then expires.

Problems

Expiry can be devilishly difficult to determine.

• Typically, a Certificate will expire on a give data and time, which seems very clear.
• When a key with a certificate is used to sign a document, should the data of validation or the date of signing be operative?
• License plates for vehicles expire every year, primarily to ensure that access taxes are collectable.

State Issued IDs

Four kinds of Identity documents are considered here among the many issued by states all over the world.

1. Passports seem to be the simplest in that they have an Expire date but cannot be used for travel starting up to 6 months before that date and are eligible for renewal up to 12 months after the expiry date.
2. Social Insurance cards typically have no expiry data other than death.
3. EID or electronic smart cards issued to state residents.
4. Driver's Licenses started out with a simple expiry date used to assure person was still qualified and able to pay.

The following Expiry dates and events can apply to a drivers license.