U.S. Army Pfc. Bradley Manning, right,  is escorted by military police as arrives to hear the verdict in his military trial. (Mark Wilson/Getty Images)

One of the charges for which a military court found Army Pfc. Bradley Manning guilty on Tuesday is computer fraud, which carries a maximum sentence of 10 years. But the nature of that conviction might surprise people who haven't been following the case closely: it all comes down to a simple little Web program that dates back to 1996.

Wget is a free, open-source program so basic that it can be run from the Web or from a file that's about half the size of an MP3 file. What it does is so simple that most Web users today wouldn't even realize this could require a separate program: It downloads files. It doesn't break into password-protected servers, secretly transmit data or steal the latest Kanye West album. The program's name is a combination of "World Wide Web" and "get," as in you use it to get files from the Internet. Its function is roughly equivalent to right-clicking something on your Web browser and then hitting "save to desktop."

Investigators found that, when Manning downloaded vast numbers of U.S. diplomatic cables and other files from the computer network he regularly accessed for his Army intelligence job, he'd used wget to do it. This doesn't mean he used wget to hack into the system – Manning already had access to the files. It means that he used this tool to download the files more efficiently. Illegally taking and distributing the files are covered under separate charges.

How does using wget qualify as computer fraud? U.S. prosecutors pointed out that wget was not on the list of "approved" programs for use in facility where Manning worked. They argued that, although Manning was allowed to access the files, using an unauthorized program to do it amounted to a digital "trespass" and thus computer fraud. They also used the fact that wget was not permitted on Manning's computer as further evidence that using it amounted to illegal computer access.

The defense tried to get this charge dismissed two weeks ago, noting that Manning hadn't stolen passwords or bypassed digital firewalls to access the documents and thus had not committed computer fraud. The judge, Col. Denise Lind, declined to throw out the charge.

That Manning was convicted of computer fraud seems to suggest that using wget on a U.S. government computer to download large numbers of files can be considered the digital equivalent of trespassing – even if it's on turf you're otherwise allowed to access.