Start with low-cost recordable storage media-rewritable DVDs and the "flash" memory used in such devices as MP3 players, for example. Add file-compression protocols that make it easy to send music, video and large texts over the Internet. Mix in free software that lets you find and download the files you want from any computer on the Web and copy them to those cheap media. It's a recipe for the end of copyright protection as we know it. What Napster has done to music is just the beginning; movies, books and games are also being reduced to so many zeroes and ones, shot around the world over the Internet and copied at will.

While the march towards a copyright-less society has seemed all but inevitable to some observers, a new technology developed jointly by IBM, Intel, Toshiba and Matsushita Electric could give control back to copyright owners. The technology, known as Content Protection for Recordable Media, or CPRM, allows content producers to specify how many times a consumer can copy a given file. When you buy and download, say, the latest album from Metallica, your MP3 player would use the rights-protection system and the serial number already on your memory card or disk to encrypt the file and create a unique "key" for it. That key lets the music player know whether or not the file is stored on an authorized disk or memory chip. When you want to listen to your album, the player checks for the digital key; if everything matches up, the file is decrypted and your music will begin to play.

The copy-protection system won't work unless it is deployed in the original files, in storage media, and in media players. Hence the need for entertainment companies, makers of storage devices and makers of media players all to license the copy-protection technology and implement the system.

Despite this daunting requirement for cooperation among disparate groups, the technology does solve a problem that some experts claimed was all but unsolvable: how to make a protection scheme that is not only cheap to deploy and easy for customers to use, but virtually hack-proof as well. The identification codes used by the copy-protection system have been part of standard storage media for many years. And the number of key combinations they provide is "greater than the number of protons in the universe," according to Jeffrey Lotspiech, research engineer at IBM's Almaden Research Center in San Jose, CA.