If you have a working key and a lock, you can take out the cylinder, look at the cuts on the pins, and get the information neccessary to make a master key on a numeric key machine.
While this technique purportedly allows you to make a master without taking the lock apart, there are few buildings where there isn't a lock on a utility closet somewhere that won't be noticed if you borrow the cylinder for 15 minutes, so I'm not really sure this makes master keyed locks stunningly more vulnerable to a determined opponent. Nonetheless, it's an interesting story. I should note that the high security building I live regards master keying doors as a bad thing to do, and they have a key board and a signout sheet in the main office. http://www.nytimes.com/2003/01/23/business/23LOCK.html l/p=cpunx/cpunx ----- A security researcher has revealed a little-known vulnerability in many locks that lets a person create a copy of the master key for an entire building by starting with any key from that building. The researcher, Matt Blaze of AT&T Labs-Research, found the vulnerability by applying his area of expertise the security flaws that allow hackers to break into computer networks to the real-world locks and keys that have been used for more than a century in office buildings, college campuses and some residential complexes. ... All that is needed, Mr. Blaze wrote, is access to a key and to the lock that it opens, as well as a small number of uncut key blanks and a tool to cut them to the proper shape. No special skills or tools are required; key-cutting machines costing hundreds of dollars apiece make the task easier, but the same results can be achieved with a simple metal file. After testing the technique repeatedly against the hardware from major lock companies, Mr. Blaze wrote, "it required only a few minutes to carry out, even when using a file to cut the keys." ... -- Eric Michael Cordian 0+ O:.T:.O:. Mathematical Munitions Division "Do What Thou Wilt Shall Be The Whole Of The Law"
