Sony United Kingdom Limited

Sony Europe Limited

Andrew Robert Taylor

Jason Charles Pelly

Daniel Luke Hooper

Daniel Warren Tapson

Jonathan James Stone

Emmanuel Alves-Moreira

The bitstream includes digital codes representing an information signal. At least one digital code is selected. The code occupies a part of the bitstream which is to contain at least one watermark code which represents a watermark perceptible in the information signal. The selected digital code(s) are removed from the said part of the bitstream. The watermark code(s) are put in the said part of the bitstream in place of the selected code(s). The number of bits of the selected code(s) removed from the said part of the bitstream is greater than or equal to the number of bits of the said watermark code(s) put in the said part. The removed selected code(s) are appended to an end of the bitstream and/or placed in watermark user data fields created in the bitstream.

Modifying bitstreams

An encoding data processing apparatus is described which is operable to generate protected compression encoded data representative of protected media signals. The apparatus comprises a data analyser which is operable 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 relatively low perceivable effect on the media signals recovered from compression decoding the compression encoded data after the selected bits had been altered. The bits are selected in accordance with predetermined criteria. The apparatus also comprises an information validation engine which is operable to form a normalised version of the compression encoded data by setting the selected data bits in the compression encoded data to a predetermined value and to generate a secure hash value of the normalised version of the compression encoded data. The information validation engine then forms the protected compression encoded data by replacing the selected data bits of the normalised compression encoded data with the data bits of the secure hash value. By generating a secure hash of the normalised bitstream rather than the original bitstream, subsequent authentication of the bitstream to verify that the bitstream has not been changed becomes possible without increasing the size of the bitstream.

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

A data encryption apparatus operable to apply encryption to input data having at least a format identifying portion and a payload portion comprises means for discriminating between the format identifying portion of the input data and the payload portion of the input data; and means for selectively applying encryption to the input data in dependence upon an output of the discriminating means so as to encrypt at least a part of the payload portion of the input data but not to encrypt the format identifying portion. A corresponding decryption apparatus is also provided.

Access control for digital video stream data

A recording system for applying access control processing to input data content and for recording access-controlled data content on a computer readable storage medium. The recording system includes an encryption apparatus for encrypting portions of the input data content and an access control memory device which securely stores information from which a private key of a public key/private key pair associated with a data content recording user or user group is derivable. The encryption apparatus and the access control memory device co-operate to provide access control data including content recorder access control data and default access control data. The default content access control data provides the same level of access to the input data content as the level of access available to the data content recording user/user group. A recorder is provided for recording the encrypted input data content and the content access control data on the computer readable storage medium.

Access control for digital content

Access to a data storage arrangement is provided in dependence upon a public/private key pair, the public key being held by the data storage arrangement and the private key by a removable memory device. The public key is securely held in a user directory of authorized users on the data storage arrangement, and is associated with a local version number. Another copy of the user directory is securely held by the removable memory device and is associated with an external version number. When the removable memory device is connected to the data storage arrangement to enable authentication, these version numbers are compared and the older version of the user directory is replaced with the later version. In this fashion updates to the list of authorized users can be propagated among suitably adapted devices without the use of a network.

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Basingstoke, United Kingdom

Andrew Robert Taylor