OT: Banc of America Article

Before you jump to the conclusion that you could just steal the black
box from the ATM and have access, but if you till it, it forgets all the
keys. Also during normal operation two separate people have to enter
two parts of the key. This way no single bank employee has access to
both parts of the key.

The product Krzystof mentions is likely similar to :

http://www-3.ibm.com/security/cryptocards/

An interesting read regarding breaking into one of these black boxes :

http://www.cl.cam.ac.uk/~rnc1/descrack/

- Mike