Method and apparatus for encrypting and decrypting time domain signals

Claim 1

A method of decrypting previously encrypted information signals to permit use thereof, said encrypted information signals comprising encrypted versions of original information signals arranged as a succession of lines of active information, each line having a line timing reference, said encrypted signals having been produced by time shifting at least some of the lines of the original information signals with respect to the line timing reference in a predetermined manner with the amount of time shifting in each line in the succession being different than that of the previous line, said decrypting method comprising the steps of: (a) providing an indication of the amount of time shifting performed on a given line; and (b) restoring the original time relationship for each line between the line timing reference and the line of information using the indication of the time shifting by generating deliberately temporally misaligned line timing reference for each line and combining said deliberately temporally misaligned line timing reference with the line of information.

Claim 2

A method of decrypting previously encrypted information signals to permit use thereof, said encrypted information signals comprising encrypted versions of original information signals arranged as a succession of lines of active information, each line having a line timing reference, said encrypted signals having been produced by time shifting at least some of the lines of the original information signals with respect to the line timing reference in a predetermined manner with the amount of time shifting in each line in the succession being different than that of the previous line, said decrypting method comprising the steps of: (a) providing an indication of the amount of time shifting performed on a given line; and (b) restoring the original time relationship for each line between the line timing reference and the line of information using the indication of the time shifting by generating deliberately temporally misaligned line timing reference for each line and combining said deliberately temporally misaligned line timing reference with the line of information.

Claim 7

A system for decrypting previously encrypted information signals to permit the use thereof, said encrypted information signals comprising encrypted versions of original information signals arranged as a succession of lines of active information, each line having a line timing reference, said encrypted signals having been produced by time shifting at least some of the lines of the original information signals with respect to the line timing reference in a predetermined manner with the amount of time shifting in each line in the succession being different than that of the previous line, said system comprising: means for providing an indication of the amount of time shifting performed on a given line; and means for restoring the original time relationship between the line timing reference and the line of information by using the indication of the amount of time shifting, said restoring means including means for generating a deliberately temporally misaligned line timing reference for each line and means for combining said deliberately temporally misalignd line timing reference with the line of information.

Claim 8

A system for decrypting previously encrypted information signals to permit the use thereof, said encrypted information signals comprising encrypted versions of original information signals arranged as a succession of lines of active information, each line having a line timing reference, said encrypted signals having been produced by time shifting at least some of the lines of the original information signals with respect to the line timing reference in a predetermined manner with the amount of time shifting in each line in the succession being different than that of the previous line, said system comprising: means for providing an indication of the amount of time shifting performed on a given line; and means for restoring the original time relationship between the line timing reference and the line of information by using the indication of the amount of time shifting, said restoring means including means for generating a deliberately temporally misaligned line timing reference for each line and means for combining said deliberately temporally misalignd line timing reference with the line of information.

Claim 11

A system for encrypting information signals to prevent unauthorized use thereof, said system receiving original information signals arranged as a succession of lines of active information, each line having a line timing reference, comprising: means for timeshifting the active information signal in each line relative to the line timing reference of that line, wherein the active information signal in each line is timeshifted by a predetermined about different from the amount of timeshifting of the previous line in the succession of lines; and means for inserting into the information signals an indication of the amount of time shifting; wherein a maximum amount of timeshifting of one line relative to any other line in the succession of lines is a predetermined about, and wherein the encrypted information signals are decryptable by a receiver, and a rate of change in the amount of time shifting between successive line is within a capture range of synchronization circuitry in the receiver.

Claim 12

A system for encrypting information signals to prevent unauthorized use thereof, said system receiving original information signals arranged as a succession of lines of active information, each line having a line timing reference, comprising: means for timeshifting the active information signal in each line relative to the line timing reference of that line, wherein the active information signal in each line is timeshifted by a predetermined about different from the amount of timeshifting of the previous line in the succession of lines; and means for inserting into the information signals an indication of the amount of time shifting; wherein a maximum amount of timeshifting of one line relative to any other line in the succession of lines is a predetermined about, and wherein the encrypted information signals are decryptable by a receiver, and a rate of change in the amount of time shifting between successive line is within a capture range of synchronization circuitry in the receiver.

Claim 19

A system for decrypting previously encrypted video signals to permit the use thereof, said encrypted video signals including time shifting of the active video portions of at least some of the lines of the video signals with respect to the synchronization portion of the lines in a predetermined manner with the amount of time shifting in each line varying from that of the previous line, comprising: means for receiving the video signal and extracting therefrom one predetermined line from a video field; means for receiving a decrypting key and the extracted line and providing therefrom time shift data relative to the television signal; means for processing the time shift data; means for generating synchronization and color burst signals in response to the processed time shift data for each line; and means for receiving the video signals and also receiving the generated synchronization and color burst signals, and for removing original synchronization and color burst signals present in the video signals and substituting the generated synchronization and color burst signals at locations which are temporally misaligned by the amount of timeshifting in each line in the video signals as determined by an output of the means for processing for each line which has been time shifted.

Claim 20

A system for decrypting previously encrypted video signals to permit the use thereof, said encrypted video signals including time shifting of the active video portions of at least some of the lines of the video signals with respect to the synchronization portion of the lines in a predetermined manner with the amount of time shifting in each line varying from that of the previous line, comprising: means for receiving the video signal and extracting therefrom one predetermined line from a video field; means for receiving a decrypting key and the extracted line and providing therefrom time shift data relative to the television signal; means for processing the time shift data; means for generating synchronization and color burst signals in response to the processed time shift data for each line; and means for receiving the video signals and also receiving the generated synchronization and color burst signals, and for removing original synchronization and color burst signals present in the video signals and substituting the generated synchronization and color burst signals at locations which are temporally misaligned by the amount of timeshifting in each line in the video signals as determined by an output of the means for processing for each line which has been time shifted.

Claim 21

A system for decrypting previously encrypted information signals to permit the use thereof, said encrypted information signals comprising encrypted versions of original information signals arranged as a succession of lines of active information, each line having a line timing reference, said encrypted signals having been produced by time shifting at least some of the lines of the original information signals with respect to the line timing reference in a predetermined manner with the amount of time shifting in each line in the succession being different than that of the previous line, said system comprising: means for providing an indication of the amount of time shifting performed on a given line; and means for restoring the original time relationship between the line timing reference and the line of information by using the indication of the amount of time shifting, said resorting means including means for generating a temporally misaligned line timing reference for each line which is temporally misaligned by the amount of timeshifting int eh encrypted version of that line, and means for combining said temporally misaligned line timing reference with the line of information.

Claim 22

A system for decrypting previously encrypted information signals to permit the use thereof, said encrypted information signals comprising encrypted versions of original information signals arranged as a succession of lines of active information, each line having a line timing reference, said encrypted signals having been produced by time shifting at least some of the lines of the original information signals with respect to the line timing reference in a predetermined manner with the amount of time shifting in each line in the succession being different than that of the previous line, said system comprising: means for providing an indication of the amount of time shifting performed on a given line; and means for restoring the original time relationship between the line timing reference and the line of information by using the indication of the amount of time shifting, said resorting means including means for generating a temporally misaligned line timing reference for each line which is temporally misaligned by the amount of timeshifting int eh encrypted version of that line, and means for combining said temporally misaligned line timing reference with the line of information.

Claim 23

A method for encrypting original information signals to prevent unauthorized use thereof, said original information signals being arranged as a succession of lines of active information, each line having a line timing reference, the method comprising the steps of: timeshifting the active information signal in each line relative to the line timing reference of that line, wherein the active information signal in each line is timeshifted by a predetermined about different form the amount of timeshifting of the previous line in the succession of lines; and inserting into the information signal an indication of the amount of time shifting; wherein a maximum amount of timeshifting of one line relative to any other line in the succession of lines is a predetermined amount, and wherein the encrypted information signals are decryptable by a receiver, and a rate of change in the amount of time shifting between successive lines is within a capture range of synchronization circuitry in the receiver.

Claim 24

A method for encrypting original information signals to prevent unauthorized use thereof, said original information signals being arranged as a succession of lines of active information, each line having a line timing reference, the method comprising the steps of: timeshifting the active information signal in each line relative to the line timing reference of that line, wherein the active information signal in each line is timeshifted by a predetermined about different form the amount of timeshifting of the previous line in the succession of lines; and inserting into the information signal an indication of the amount of time shifting; wherein a maximum amount of timeshifting of one line relative to any other line in the succession of lines is a predetermined amount, and wherein the encrypted information signals are decryptable by a receiver, and a rate of change in the amount of time shifting between successive lines is within a capture range of synchronization circuitry in the receiver.