Data processing apparatus and method for generation of protection compression encoded data

A decoding data processing apparatus configured to validate protected media signals by decoding protected compression encoded data representative of the protected media signals, the protected compression encoded data containing validation data, the validation data having been calculated by identifying selected data bits in the compression encoded data in accordance with predetermined criteria which when altered would have a low perceivable effect on the media signals, replacing each of the selected data bits 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 form a normalised version of the received compression encoded data representative of the media signals, calculating 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 replacing the selected data bits of the normalised version of the compression encoded data with the data bits of the secure hash value to form the protected compression encoded data so that the secure hash value is derivable from the selected data bits in the protected compression encoded data,

• the apparatus comprising:
• a data analyzer configured to receive the protected compression encoded data and to identify selected data bits in the protected compression encoded data in accordance with the predetermined criteria,
• an authentication engine configured
• to extract the validation data from the selected bits,
• to form a normalised version of the validated compression encoded data representative of the media signals by setting the selected bits in the validated compression encoded data to the fixed predetermined value,
• to calculate a hash value of the normalised version of the validated compression encoded data representative of the media signals, and
• to compare the extracted validation data with the calculated hash value, the protected compression encoded data being verified as valid when the validation data and the calculated hash value match.

An encoding data processing method for generating protected compression encoded data representative of protected media signals, the method comprising:

• receiving compression encoded data representative of the media signals,
• identifying selected data bits in the received compression encoded data which when altered would have a low perceivable effect on the media signals recovered from compression decoding the received compression encoded data after the selected bits had been altered, the selected bits being selected in accordance with predetermined criteria,
• forming a normalised version of the received compression encoded data representative of the media signals by replacing each of the selected 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,
• calculating a secure hash value of the normalised version of the received compression encoded data which includes, at the selected data bits representing dais low perceptibility data bits, said fixed predetermined values and which is representative of the media signals, and
• forming 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.

A decoding data processing method for validating protected media signals by decoding protected compression encoded data representative of the media signals, the compression encoded data containing validation data, the validation data having been calculated by identifying selected data bits in the compression encoded data in accordance with predetermined criteria which when altered would have a low perceivable effect on the media signals, replacing each of the selected data bits 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 form a normalised version of the received compression encoded data, calculating a secure hash value of the normalised version of the compression encoded data which includes, at the selected data bits representing said low perceptibility data bits, said fixed predetermined values and replacing the selected data bits of the normalised version of the compression encoded data with the data bits of the secure hash value to form the protected compression encoded data so that the secure hash value is derivable from the selected data bits in the protected compression encoded data, the method comprising:

• receiving the protected compression encoded data,
• identifying selected data bits in the protected compression encoded data in accordance with the predetermined criteria,
• extracting the validation data from the selected bits,
• forming a normalised version of the protected compression encoded data representative of the media signals by setting the selected bits in the protected compression encoded data to the fixed predetermined value,
• calculating a hash value of the normalised version of the protected compression encoded data representative of the media signals, and
• comparing the extracted validation data with the calculated hash value, the protected compression encoded data being verified as valid when the validation data and the calculated hash value match.