Prevention of disk piracy

Apparatus for protecting data recorded on an original data storage medium against unauthorized copying, comprising an error generator, which receives data encoded in accordance with an applicable recording standard and alters a portion of the encoded data prior to recording of the data on the medium such that the altered data are identified as erroneous according to the standard,

• wherein the data recorded on the medium include ancillary data, which are used by a processor in an intended application of the medium to operate upon the altered portion of the data such that the application runs in a manner substantially unaffected by the alteration of the data, but which ancillary data are ineffective in correcting the altered portion of the encoded data upon copying of the data, so that the alteration causes a substantially unrecoverable error in an unauthorized copy of the original medium.

Apparatus for protecting data recorded on an original data storage medium against unauthorized copying, comprising an error generator, which receives a stream of modulated data in a format for driving a recording device used in a process of recording the data on the medium in accordance with an applicable recording standard, and which alters a portion of the encoded data prior to recording of the data on the medium and outputs the data including the altered portion to the recording device, modulated in the format in accordance with the standard.

A data storage medium that is resistant to unauthorized copying, on which medium data encoded in accordance with an applicable recording standard are stored, a portion of which encoded data is altered such that the altered data are identified as erroneous according to the standard, the stored data including ancillary data which are used by a processor in an intended application of the medium to operate upon the altered portion of the data such that the application runs in a manner substantially unaffected by the alteration of the data, but which ancillary data are ineffective in correcting the altered portion of the encoded data upon copying of the data from the medium, so that the alteration causes a substantially unrecoverable error in an unauthorized copy of the medium.