In an effort to protect its copyright material for digital distribution, Universal Music Group is preparing to incorporate technology that may keep consumers from playing their legally bought CDs over their PCs at work or at home as soon as next month. The digital rights management technology that Universal Music Group is most closely considering is called Cactus Data Shield, from the Israeli company Midbar Tech, according to a source close to Universal. The technology would be used to scramble the data on an audio CD so that CD and DVD drives used by PCs can't play them. The technology is expected to be applied to at least one new CD release from Universal before the end of the year, with production to be ramped up after that, the source said. Consumer-advocate campaigners, such as U.K.-based Campaign for Digital Rights, are concerned that it is simply a matter of time before the major music companies use such technology as a matter of course to keep consumers from playing legally bought CDs over their PCs at work or at home. Music companies may do so, the consumer advocates say, without warning consumers or lowering the price of a CD that some users may find less useful.