Sony BMG Music's controversial copy-protection scheme can be defeated with a small piece of tape, a research firm said Monday in a demonstration of the futility of digital rights management (DRM).

According to Gartner analysts Martin Reynolds and Mike McGuire, Sony's XCP technology is stymied by sticking a fingernail-size piece of opaque tape on the outer edge of the CD.

That, the pair said in a brief posted online, renders "session 2 -- which contains the self-loading DRM software — unreadable. The PC then treats the CD as an ordinary single-session music CD, and the commonly used CD 'rip' programs continue to work as usual."

Such simple work-arounds, said Reynolds and McGuire, make Sony's decision to copy protect is music CDs an even bigger mistake. "Sony BMG's DRM technology will prevent neither informed casual copiers nor high-volume 'pirates' from doing whatever they like with the content the disc," the analysts continued. "It does, however, load 'stealth' software — software that has been demonstrated to have suspect effects — on uninformed users' machines.

"The bottom line: Sony BMG has created serious public-relations and legal issues for itself, and for no good reason."

Only after 10 days of mounting criticism about its surreptitious installation of a hacker-style "rootkit" to users' PCs did Sony announce that it would end the copy-protection; a week later it said it would recall all unsold CDs and exchange those already in consumers' hands with unprotected discs.

Sony's exchange program also gives buyers of the 52 in-question CDs the option of receiving unprotected MP3 files of the album's tracks, in large part because the disc exchange process takes three to six weeks.

Those users will receive an e-mail directing them to a site where they can download the MP3 files, Sony said on its exchange program Web page.

This isn't the first time that simple methods have defeated a Sony copy-protection plan. An earlier technology that Sony used could be circumvented by using a black marker to draw a line near the edge of the disc.

"After more than five years of trying, the recording industry has not yet demonstrated a workable DRM scheme for music CDs," concluded the Gartner analysts. "It will never achieve this goal as long as CDs must be playable by stand-alone CD players."