| 摘要 |
The invention relates to a method of obtaining a copy protected optical record carrier carrying information in different blocks, a method of accessing such a copy protected optical record carrier and such an optical record carrier itself. Access means for optical record carriers return different results when retrievin g blocks, which contain incorrect address data in the corresponding subcode fields. A copy protection key will be implemented during manufacture of an optical record carrier by modifying the subcode address information of a predete rmined pattern of blocks. It is normally not possible to copy incorrect address data onto an optical record carrier, since the address data will be newly genera ted during the copy process. Therefore, such a key can be utilized to distinguish between an original disc and a copied or non original disc. The key is preset before manufacturing of the optical record carrier itself and can therefore be used to encrypt the data stored on the optical record carrier. Upon accessing of the data, first the key is extracted from the optical record carrier and then the data can be decrypted utilizing this key.
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