[Cryptography] Possible reason why password usage rules are such a mess

[Howard Chu]

John Levine wrote:
> In article <69b8ae4f-962c-a1d6-9532-99bef1a8a1db at symas.com> you write:
>> This one is easy - you can't travel with an expired photo ID because the possibility
>> exists that someone else is already traveling with the valid ID.
> 
> Assuming the someone else isn't your identical twin, could you explain
> in more detail how that works?
> 
> There are reasons for driving licenses to expire and be renewed, since
> your authority to drive might be limited or revoked.  But unless you
> die, it's hard to see what's going to revoke your authority to be
> yourself.

An expired photo ID has to be considered the same as a forged ID or a
counterfeit, because there's a high probability that the corresponding
new/renewed ID exists and is in circulation.

As for identical twin - come on... People don't check that closely, or
your own appearance changes over the years.

IDs have to be unique. The attempt to use an expired ID means it can no
longer be relied on to be unique; the non-expired one is out there somewhere,
possibly being concurrently used by someone else.

-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/