Patent ID: 7434052

Claim:
Method for producing a payload data stream comprising a header and a payload data block containing encrypted payload data, comprising the following steps: generating a payload data key for a payload data encryption algorithm for encrypting payload data, the payload data having a first section and a second section, the first section and the second section including audio data, video data, a combination of audio data and video data, or binary data forming an executable program; encrypting the audio data, video data, a combination of audio data and video data, or binary data forming an executable program of the first section of the payload data using said payload data key and said payload data encryption algorithm to obtain an encrypted section of said payload data block of said payload data stream, wherein the second section of the payload data remains unencrypted; processing the audio data, video data, a combination of audio data and video data, or binary data forming an executable program of the unencrypted second section of said payload data to deduce information characterizing the unencrypted second section of said payload data; linking said information and said payload data key by means of an invertible logic linkage to obtain a basic value; encrypting said basic value using a key of two keys being different from each other by an asymmetrical encryption method, said two different keys being the public and the private keys respectively for said asymmetrical encryption method, to obtain an output value being an encrypted version of said payload data key; and entering said output value into said header of said payload data stream.