The memory card doors on Diebold voting machines are physically secured using a mailbox lock. Freedom to Tinker has the details on how you can make your own key:
According to published reports, nearly all the machines deployed around the country use the exact same key. Up to this point we’ve been careful not to say precisely which key or show the particular pattern of the cuts. The shape of a key is like a password — it only provides security if you keep it secret from the bad guys. We’ve tried to keep the shape secret so as not to make an attacker’s job even marginally easier, and you would expect a security-conscious vendor to do the same.
Not Diebold. Ross Kinard of SploitCast wrote to me last month to point out that Diebold offers the key for sale on their web site. Of course, they won’t sell it to just anybody — only Diebold account holders can order it online. However, as Ross observed, Diebold’s online store shows a detailed photograph of the key.
These are the same people who probably furnished your bank’s ATMs as well. Comforting.