AudioLok - The next CD Protection for Audio CD's
IF YOU LIKE
LISTENING to music
CDs while working on your computer, New Scientist has some
bad news: a company has found a way of preventing CDs being played
on a computer's CD-ROM drive. The idea is not to increase
productivity in the office, but to stop pirates copying CDs or
sending CD-sourced music across the Internet. It is not yet clear,
however, whether record companies will risk consumers' wrath by
releasing discs they can't play on their PCs.
Software companies, including Micro- soft and IBM-owned Lotus,
already use C-Dilla's SafeDisc system to stop people copying
CD-ROM data discs. SafeDisc puts the program material in an
encrypted "wrapper" which can only be unwrapped when a
digital signature code pressed into the disc matches an
authorisation code entered into the PC. While a ROM drive can read
the authorisation code, a CD recorder cannot copy it, so copies of
the CD-ROM will not run.
A CD-ROM disc stores data at three levels, and although a CD-ROM
drive reads all three, it only passes the top level into a PC for
copying. SafeDisc stores the key code signature at a lower level,
so it can be read from the original CD-ROM disc but not copied
onto a blank. Although a CD recorder can copy a protected disc,
the copy will not run on a PC even when the correct authorisation
code is entered.
The music industry has been dreaming of just such an anticopy
system since it was claimed more than 30 years ago that the
Beatles' vinyl album Sergeant Pepper could not be copied.
In fact, as with the many systems that followed, the recording was
as easy to copy as it was to play.
But now C-Dilla's founder Peter Newman, who invented SafeDisc, has
found an answer for the CD generation. His Audio-Lok system takes
advantage of the fact that the standard for the music CD format
was set before the CD-ROM standard.
CD-ROM drives have a more powerful error-correction system than
music CD players, which is activated by extra code on the CD-ROM
discs. Newman's system adds false error codes to a music disc. An
ordinary CD player doesn't notice the false codes, but a CD-ROM
drive picks them up and ejects the disc as unplayable. This makes
it impossible to copy the music onto a blank disc or
"rip" it onto a computer so it can be compressed and
sent over the Net.
A prototype AudioLok disc lent to New Scientist duly played
on a CD music player but refused to play or copy on a PC. Newman
says he is confident that his system will also stop consumer music
CD recorders making a copy, because these devices are already
designed not to copy CD-ROMs. He expects AudioLok to be ready for
launch in a year.
TV and video companies already use a copy-protection system,
developed by the American company Macrovision, to stop people
pirating their programs and movies. Macrovision has bought C-Dilla
for around $18 million so it can offer similar protection to the
But the breakthrough may have come at the wrong time. The music
industry's Secure Digital Music Initiative group has just agreed
with the electronics manufacturers to allow owners of CDs to make
copies onto a PC, as there seemed to be no foolproof way to stop
So will music companies use AudioLok? "The recording industry
welcomes people listening to CDs on computers," says Paul
Jessop, director of technology at the International Federation of
the Phonographic Industry, the music industry's world trade body.
But he adds: "The ability to make discs that cannot be copied
on computers may be of considerable interest to some record