A software company has dropped a threat to sue a US student who published details on how to get around anti-piracy technology on a new music CD. The company behind the software, SunnComm Technologies, said it did not want to hamper academic research. Last week computer science graduate John Halderman showed how to defeat the copy-protection software by pressing a single computer key.

Several firms are looking at ways to make it harder to share music online.

Mr Halderman found that SunnComm's MediaMax CD-3 software could be bypassed by holding down the shift key on a Windows PC when a copy-protected CD was inserted.

This temporarily disables the autorun function on Windows, stopping a anti-piracy program from installing itself on the computer.

SunnComm has originally said it was going to sue to Mr Halderman for revealing the secrets of the anti-piracy measures.

But following publicity surrounding the case, the company's boss has backed away from the threat of legal action.

"It wasn't our intention to strike a blow against research," Peter Jacobs told the news agency Reuters.

"We sincerely thought that the research was not founded on the premise for which the technology was invented in the first place."

"(The research) doesn't dilute our technology at all, nor does it nullify our technology."

The music industry blames falling CD sales on digital piracy and file-sharing online.

It is looking at new technologies to stop what it sees as rampant copying of compact discs and the sharing of those files online.

But so far, most technologies developed to protect music against copying have fallen short.