Guest mode with different passprhases

[Hans-Christian Esperer]

Hi all,

I'd like to achieve the following:

A wifi where both regular users and guests can log in. All users should use
PEAP to establish an encrypted connection. Normal users then use a combination
of username,passphrase, nothing unusual here.

Guests, however, shall be able to login with username "guest" and a PIN number
as passphrase. Several PIN numbers should be allowed, but each PIN number only
once, or for a certain amount of time after the first usage.

The idea is that each guest is assigned a PIN number to be used once, when they
need access, and upon first usage of that PIN it is deleted or marked as used
in a database and cannot be used a 2nd time. PINs should be randomly generated
as needed.

Is this at all possible? If so, how would one best implement it? Writing your
own Perl module? Is there something available in the default distro to achieve
this behavior?

Thanks in advance,
 HC