The Secret Service not only protects the President and other dignitaries - they also protect the nation's funds from fraud. National Geographic's Secret Service Files explains how the agency fights credit card fraud and financial hacking using advanced technology.

Compact and discreet credit card skimmers have become increasingly prevalent, quickly storing personal information for criminal use. Often, fraudulent scanners are placed over real scanners on ATM machines, or as this clip shows, in restaurants where the waitstaff keeps a customer's card for minutes at a time. The stolen information can then be copied to blank credit cards called "white plastic," which are often difficult to detect.

But the credit card skimmers are really just small-fry stuff. The Secret Service has focused more and more on large internet schemes, like those involving trojan horse software attached to spam email. These emails result in a ton of stolen personal information, and that data is then sold in bundles for cash. If the Secret Service is lucky enough to apprehend a lower-level figure in such a scheme, their only hope of finding the big hacker involves some hacking of their own - dissecting hard drives bit by bit for any available clues.

Secret Service Files premieres Sunday, February 20th, on National Geographic Channel.