OT: detecting bad WEP passwords

[Tony Espy]

I know this is slightly off-topic, but I figure someone on this list 
might know the answer...

Does anyone know how OS X detects that a WEP password is bad?  I was 
under the assumption that there's no way to determine that a WEP 
password was bad using Open Key Authentication.  My boss just won $10 of 
  me when he typed in an incorrect password for a WEP AP, and OS X told 
him that the password was incorrect.

Normally, when the password is bad, DHCP fails because the packets sent 
to the DHCP server cannot be decrypted by the AP, and hence DHCP 
eventually times out.  I'm not sure how to tell the difference between 
this scenario, and the scenario where the password is correct, but 
there's no DHCP server on the network ( or the AP's ethernet cable is 
unplugged ).

thanks,
Tony Espy
Pepper Computer