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SunnComm Out To Plug CD’s Analog Security Hole

Consumers who would use their PC’s analog-audio outputs to circumvent digital copy-protection technologies might soon lose that option.

SunnComm, which developed MediaMax CD-3 copy-control technology used by BMG on select commercial CDs, hopes to combine its technology with Dark Noise technology to plug what it calls the “analog hole” exploited by PC users.

The technology, however, would also prevent users of home-audio CD-recorders from dubbing CDs via the recorder’s analog inputs. If music companies adopt the technology, it could be a violation of the Audio Home Recording Act (AHRA), passed in the early 1990s.

On BMG discs, SunnComm’s technology lets users play the CD’s uncompressed PCM tracks on nearly all standard playback devices, including CD players, DVD players, and the like. On a PC, however, playback of the uncompressed music is blocked, but the PC is allowed to play a duplicate “second session” of tracks in compressed copy-protected Windows Media Audio (WMA) format. In BMG’s implementation, the protected tracks can be transferred to a PC’s hard drive, transferred to a compatible portable music device, and burned to up to three blank CD-R discs.

Once the music passes through an analog output, however, it “may be resampled to another PC, captured by software in memory, or recorded from the speaker/preamp output and reconverted to a digital format for copying,” SunnComm president Peter Jacobs said.

To plug this “analog hole,” SunnComm marketing agent Quiet Tiger plans to buy DarkNoise Technologies of the United Kingdom and its copy-protection technology.

DarkNoise technology works like this: a hidden signal is embedded directly in the music of an audio master and transferred to commercial CDs. If the protected commercial CDs are copied through a PC’s analog outputs — using analog recording devices, A/D converters, or MP3 encoders — the hidden signal becomes audible. “The typical result would be an irritating high-pitched tone” that would be audible while the music is playing, said SunnComm CTO Eric Vandewater.

The same result would occur in certain circumstances when a consumer uses a home audio CD-recorder, whose copy-protection systems were mandated under the AHRA. The act permits CD recorders to make first-generation digital-to-digital dubs. It also mandates Serial Copy Management System (SCMS) technology that prevents the recorders from making serial digital copies of the first-generation copy. Unlimited serial copying of a dubbed disc, however, is allowed if the copied disc’s content is converted from digital to analog and than back to digital for recording onto a blank CD.

“I can’t answer the legal ramification,” Vandewater said. “It would be up to the record labels to work it out.” But since the early 90s, he noted, “the whole market has shifted dramatically.” He also said the technology “ensures fair-use possibilities,” and the AHRA “is all about fair use.”