| 摘要 |
Encrypted data on a CD-PROM disk is managed by selectively encoding binary digital decryption keys (65) onto the same disk in a separate data area. A decryption key or keys (65) may be programmed onto the disk after manufacture, such as at the point of sale, by selectively obliterating the readability of bits in addressable sectors. A binary digital key (65) is then later recognized as the result of a string of addressable sectors, with one or the other of readable or unreadable sectors being recognized as a logical 1 and the other as a logical 0. In an embodiment, a manufacturer may place several or all versions and features of a large program on a single CD-ROM, encrypted, and later provide keys (65) to enable only selected ones of the features (66) and versions (66) for retrieval.
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