Patent ID: 8046580

Claim:
An encoding data processing apparatus configured to generate protected compression encoded data representative of protected media signals, the apparatus comprising: a data analyzer configured to receive compression encoded data representative of the media signals and to select low perceptibility data bits in the compression encoded data which when altered would have a low perceivable effect on the media signals recovered from compression decoding the compression encoded data after the selected bits had been altered, the selected bits being selected in accordance with predetermined criteria, an information validation engine configured to form a normalised version of the received compression encoded data representative of the media signals by replacing each of the selected data bits in the compression encoded data with data bits of a fixed predetermined value, the fixed predetermined value of each of the selected data bits being chosen without regard to the value of the selected data bits of the compression encoded data, to generate a secure hash value of the normalised version of the received compression encoded data which includes, at the selected data bits representing said low perceptibility data bits, said fixed predetermined values and which is representative of the media signals, and to form the protected compression encoded data by replacing the selected data bits of the normalised compression encoded data with data bits of the secure hash value so that the secure hash value is derivable from the selected data bits in the protected compression encoded data.