Cryptography – Video cryptography – Video electric signal modification
Reexamination Certificate
1998-10-26
2004-05-11
Hayes, Gail (Department: 2131)
Cryptography
Video cryptography
Video electric signal modification
C380S201000, C705S051000, C705S052000
Reexamination Certificate
active
06735311
ABSTRACT:
FIELD OF THE INVENTION
The present invention refers to the ciphering and deciphering of multimedia data and in particular to the ciphering and deciphering formats which can be used e.g. in the commercial marketing of multimedia data.
BACKGROUND
With the appearance of telecommunication networks and in particular because of the widespread use of personal computers capable of handling digital multimedia data, a need arose for the commercial marketing of multimedia data, such as e.g. digital audio data or digital video data. The telecommunication networks may e.g. be analog telephone lines, digital telephone lines, such as ISDN e.g., or also the Internet. On the part of commercial providers of multimedia products there is the need to sell or hire out multimedia data in such a way that a customer should be able to choose a certain product individually from a certain catalogue at any time, only the customer who pays for it being able to use the product of course.
In contrast to the known ciphered television programmes, such as e.g. the television channels Premiere or MTV, where the broadcast data are ciphered identically for all users, who have acquired a suitable deciphering device for an appropriate fee, the present invention provides methods and devices which make possible an individual, customer-selective ciphering and deciphering of multimedia data. In contrast to the cited television channels, which offer a fixed programme which the user must accept or reject in its entirety, the methods and devices of the present invention offer the customer a maximum freedom of choice, i.e. he must only pay for those products which he has actually used.
U.S. Pat. No. 5,369,702 discloses a system for increasing the security of a computer system in which individual users can utilize the system flexibly and efficiently. The method disclosed in this publication comprises the steps of accessing an object-oriented key administrator, selecting an object to be ciphered, selecting a label for the object, selecting an ciphering algorithm, ciphering the object according to the ciphering algorithm, labelling the ciphered object, reading the object label, determining an access authorization on the basis of the object label and deciphering the object if the access authorization is granted. A file “label” consists of a series of letters or numbers, which may be ciphered or not ciphered. This file label is separate from a message but is assigned to the transmission of the message, the label also identifying the person, position, equipment and/or organization entitled to receive the assigned message, i.e. the multimedia data.
U.S. Pat. No. 5,319,705 relates to a method and a system for the secure distribution of a plurality of software files from a software distribution processor to a user processor, while the user processor is selectively enabled to use only a subset of a smaller plurality of software files. This is achieved by using a customer key having an unciphered customer key and a derived section which is derived from the customer number.
It is the object of the present invention to provide methods and devices for ciphering and deciphering multimedia data which, on the one hand, guarantee an effective copyright protection, and which, on the other, are capable of ciphering and deciphering individually requested data flexibly.
SUMMARY OF THE INVENTION
According to a first aspect of the present inventions method for ciphering multimedia data to obtain an ciphered multimedia file having a definition data block and a multimedia data block, comprising the steps of entering a definition data ciphering index in the definition data block which points to a definition data ciphering algorithm to be used for ciphering a section of the definition data block; entering a multimedia data ciphering index in the definition data block which points to a multimedia data ciphering algorithm to be used for ciphering at least part of the multimedia data block; entering a free index in the definition data block, the free index identifying a particular deciphering device with which the ciphered multimedia data can be deciphered beyond a specified period of time; selecting the definition data ciphering algorithm from a plurality of ciphering algorithms on the basis of the definition data ciphering index; selecting the multimedia data ciphering algorithm from a plurality of ciphering algorithms on the basis of the multimedia data ciphering index; ciphering the section of the definition data block with the definition data ciphering algorithm, the section of the definition data block not including the definition data ciphering index; and at least partially ciphering the multimedia data block with the multimedia data ciphering algorithm.
According to a second aspect of the present invention a method for deciphering multimedia data contained in a multimedia file having a definition data block and a multimedia data block, the definition data block including a definition data ciphering index, a multimedia data ciphering index, and a free index, comprises the steps of reading the definition data block; selecting a definition data deciphering algorithm from a plurality of deciphering algorithms on the basis of the definition data ciphering index; selecting a multimedia data deciphering algorithm from a plurality of deciphering algorithms on the basis of the multimedia data ciphering index; deciphering the ciphered section of the definition data block using the definition data deciphering algorithm; and deciphering the multimedia data block using the selected multimedia data deciphering algorithm, wherein the step of deciphering the multimedia data block is only continued beyond a specified period of time if the device for deciphering has a setting which is appropriate for the free index.
According to a third aspect of the present invention a device for ciphering multimedia data to obtain a ciphered multimedia file having a definition data block and a multimedia data block, comprises means for entering a definition data ciphering index in the definition data block, the definition data ciphering index pointing to a definition data ciphering algorithm to be used for ciphering a section of the definition data block; means for entering a multimedia data ciphering index in the definition data block, the multimedia data ciphering index pointing to a multimedia data ciphering algorithm to be used for ciphering at least part of the multimedia data block; means for entering a free index in the definition data block, the free index identifying the device for deciphering with which the ciphered multimedia data can be deciphered beyond a specified period of time; means for selecting the definition data ciphering algorithm from a plurality of ciphering algorithms on the basis of the definition data ciphering index; means for selecting the multimedia data ciphering algorithm from a plurality of ciphering algorithms on the basis of the multimedia data ciphering index; means for ciphering the section of the definition data block with the definition data ciphering algorithm, the section of the definition data block not including the definition data ciphering index; and means for at least partially ciphering the multimedia data block with the multimedia data ciphering algorithm.
According to a fourth aspect of the present invention a device for deciphering multimedia data contained in a multimedia file having a definition data block and a multimedia data block, the definition data block including a definition data ciphering index, a multimedia data ciphering index, and a free index, comprises: means for reading the definition data block; means for selecting a definition data deciphering algorithm from a plurality of deciphering algorithms on the basis of the definition data ciphering index; means for selecting a multimedia data deciphering algorithm from a plurality of deciphering algorithms on the basis of the multimedia data ciphering index; means for deciphering the ciphered section of the definition data block using the definition data deciphering a
Popp Harald
Rump Niels
Zeller Jürgen
Fraunhofer-Gellschaft zur Forderung der Angewandten Forschung E.
Glenn Michael A.
Glenn Patent Group
Hayes Gail
Seal James
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