Also, sometimes private encryption keys are stolen, he says. One issue is that encryption keys in content-delivery systems are often defined in software, not hardware, which makes them easier to compromise.

Another concern is that the activation and anti-piracy hardware for user TV set-top boxes or specialty boxes for streaming content is so "chip-vendor" specific that it only works for one or a very limited number of content providers.

A better approach would be to have multiple encryption keys for use by multiple service providers stored on a chipset, Kocher says. One example of this "security on a chipset" idea today has been devised by STMicroelectronics. Its next-generation STi7108 decoder chips boast a 3D graphics engine and access to external storage like flash and hard-disk drives for hybrid Internet/broadcast TV set-top boxes that let the user easily navigate between hybrid Internet, broadcast TV and personal content. It's not the way that home entertainment is generally enjoyed today, but it might be in the future.

Ellen Messmer is senior editor at Network World, an IDG publication and website, where she covers news and technology trends related to information security. Twitter: MessmerE. E-mail: emessmer@nww.com.

in Network World's Wide Area Network section.