Ryan Harris—known by the alias DerEngel—is an expert on cable modem hacking, an art that he describes at length in a 2006 instructional guide that was published by No Starch Press. He runs a small company that sells unlocked cable modems with custom firmware and provides instructional material that explains how to manipulate the devices in various ways.

Although there are plenty of valid reasons for users to want complete access to their network hardware, cable modem hacking can also be used to circumvent ISP-imposed bandwidth caps and obtain free service through MAC address spoofing. In an apparent crackdown on cable modem hacking, law enforcers have brought criminal charges against Harris, accusing him of wire fraud and computer fraud. The basis for these charges, says the indictment, is that Harris aided and abetted others in accessing a protected computer without authorization with the intent to defraud.

The case raises the question of whether a company that mods hardware should be held responsible when their customers abuse the modded products for dubious purposes. Harris contends that his modded modems and custom firmware have a multitude of legitimate uses. In an interview with Wired's Threat Level blog, he claimed that the government's move to prosecute him for selling unlocked cable modems would be like "arresting every firearms dealer, because handguns can be used to commit murder."

The indictment, however, alleges that Harris had direct involvement in assisting at least one of his customers with cable hacking. It also alludes to a message he posted in the public forums of his company's website in which he sought a valid MAC number for a particular region—something that would theoretically only be useful for MAC spoofing.

The FBI has previously taken action against users who have "uncapped" their cable modems in order to get faster network speeds. One of the earliest cases dates back to a set of raids that took place in Toledo, Ohio in 2002. It's unclear, however, if merely providing unlocked modems that can potentially be used for uncapping is really a criminal offense.

It may be a question of subtlety. The fact that one of the programs he sells is called "Coax Thief" may not win him too much sympathy from a jury. Harris says that he plans to plead not guilty.