Copy lock.

• Author: Harmon, Amy
• Position: Circuits - Brief Article

The next music CD you buy won't have a big "copy protected" sticker, but it could have a high-tech lock on it just the same. With little publicity, the recording industry has begun selling CDs designed to make it impossible for people to copy music to their computers, trade songs over the Internet, or transfer them to portable MP3 players.

One version of the technology inserts distortions into the music that can't be detected on an ordinary CD player. But those distortions make clicking and popping...