Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

Niels Rump

Juergen Koller

Juergen Herre

Harald Popp

Karlheinz Brandenburg

Eric Allamanche

J&uuml;rgen Zeller

In a method for producing an encrypted method payload data stream comprising a header and a block containing encrypted payload data, a payload data key for a payload data encryption algorithm for encrypting payload data is generated. The payload data is encrypted using the generated payload data key and the payload data encryption algorithm to obtain the block containing the encrypted payload data of the payload stream. A part of the payload data stream is processed to deduce information marking the part of the payload data stream. The information is linked with the payload data by means of an invertible logic linkage to obtain a basic value. This basic value is finally encrypted using a key of two keys being different from each other by an asymmetrical encryption method, the two different keys being the public and the private keys respectively for the asymmetrical encryption method to obtain an output value being an encrypted version of the payload data key. The output value is finally entered into the header to complete the payload stream. Changes of the header and of the payload data itself, which are not authorized, lead to an automatic destruction of the payload data.

Method and device for producing an encrypted payload data stream and method and device for decrypting an encrypted payload data stream

An apparatus for generating an encrypted data stream representing an audio and/or video signal comprises an encoder for encoding an input signal to generate a data stream with a predefined data stream syntax as output signal. The apparatus further comprises an encryption means coupled with the decoder in order to influence encoder internal data and/or the output signal of the encoder in a uniquely reversible manner based on a key such that the generated encrypted data stream comprises payload information differing from payload information of a data stream that would be generated by the apparatus without the presence of an encryption means and that the generated encrypted data stream comprises the predefined data stream syntax. Thereby, a flexible data stream encryption is achieved, wherein the degree of encryption can be freely selected such that the owner of a decoder who does not possess the key, still obtains a rough idea of the audio and/or video signal which might cause him to buy the key in order to hear or view the audio and/or video signal in its full quality. The encoder-specific encryption and decryption concept can be implemented into already existing encoders/decoders with little effort.

Device and method for producing an encoded audio and/or video data stream

In a method for generating a second data stream from a first data stream, which comprises a first header and a first payload data block with payload data, the first header is initially extracted from the first data stream. Subsequently the second header for the second data stream is generated. Then, at least a part of the first header is entered into the second header, the part of the first header including information, which allows conclusions as to the origin of the payload data. Finally, the second payload data block is generated, which comprises the same payload data, so as to obtain the complete second data stream. The method according to the invention enables device-specific encrypting of payload data, a flexible, device-specific 'copy' for other devices of a user and, in particular, complete documentation of the origin of the present copy, such that effective copyright protection may be realized.

Method and device for generating a data stream and method and device for playing back a data stream

A method for ciphering multimedia includes the entering of an ciphering index in a definition data block of the multimedia data, this index pointing to an ciphering algorithm which is to be used. In response to the ciphering index in the definition data block one of a plurality of ciphering algorithms is selected. The multimedia data are ciphered using the selected ciphering algorithm. Various additional entries in the definition data block which is assigned to the multimedia data permit the clearing or enabling of a deciphering device, rapid access to a database of ciphered multimedia data and a customer- and data-specific use of the multimedia data while taking copyright aspects into account.

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Bromley, United Kingdom

Niels Rump