[DanBC]

Yes. There was a recent thread where this process is explained. I'll try to find it, but basically:

You have one lock, and one key (not the master) for that lock, and a bunch of blanks.

You take the first blank. You cut a key that is identical to your key, except you vary the depth of a single cut. You repeat this until this new key works in your lock. That gives you the master key cut depth of one part of the key. You repeat this process forthe rest of the positions. You end up with a master key.

Edit: MrJones' comment here: https://news.ycombinator.com/item?id=10186309

[duskwuff]

Slightly different process. The TSA keys aren't "master keys" in the normal locksmithing sense; they typically go into a separate lock that's only used for that key. For instance, the lock pictured in the article is normally used as a combination lock, not a key lock.

[DanBC]

You buy one lock and take it apart?

[akira2501]

Yep. The "security" is that compromised; leaked photographs or no.

[JasuM]

Awesome! I didn't even think that you could do that without breaking the lock apart.