Method and device for controlling distribution and use of digital works
First Claim
1. A method for controlling distribution and use of a digital work (DW), comprising the steps of:
- a) attaching a usage right information to said digital work (DW), said usage write information defining one or more conditions which must be satisfied in order for said usage right to be exercised;
b) storing said digital work (DW) and its attached usage right information on a record carrier (10);
c) updating said attached usage right information with every use of said digital work (DW); and
d) refusing the use of said digital work if said usage right information indicates that the usage right has been exercised;
characterized in that e) a hidden information (KLK) stored in a hidden channel and used for encrypting or verifying said usage right information is changed when said usage right information has changed.
5 Assignments
0 Petitions
Accused Products
Abstract
The present invention relates to a method and device for controlling distribution and use of a digital work stored together with an attached usage right information on a record carrier. The attached usage right information is encrypted or verified by using a hidden information which is changed at every change of said usage right information. The hidden information may be an encryption key used for encrypting the usage right information, or a checksum of a data block containing the usage right information. Thus, a “copy and restore attack” is not successful, since it will lead to a mismatch between the hidden information and the restored usage right information.
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Citations
13 Claims
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1. A method for controlling distribution and use of a digital work (DW), comprising the steps of:
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a) attaching a usage right information to said digital work (DW), said usage write information defining one or more conditions which must be satisfied in order for said usage right to be exercised;
b) storing said digital work (DW) and its attached usage right information on a record carrier (10);
c) updating said attached usage right information with every use of said digital work (DW); and
d) refusing the use of said digital work if said usage right information indicates that the usage right has been exercised;
characterized in thate) a hidden information (KLK) stored in a hidden channel and used for encrypting or verifying said usage right information is changed when said usage right information has changed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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- 11. A record carrier for storing a digital work (DW) and a usage right information defining one or more conditions which must be satisfied in order for the usage right to be exercised, characterized in that said recording carrier (10) comprises a hidden channel which is not accessible by a commercial reproducing devices and in which a hidden information (KLK) is stored which is used for encrypting or verifying said usage right information and which is changed when said usage right information has changed.
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13. A device for controlling distribution and use of a digital work, comprising:
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a) writing means (20) for writing said digital work (DW) and an attached usage right information defining one or more conditions which must be satisfied in order for the usage right to be exercised, on a record carrier (10);
b) updating means (22) for updating said attached usage right information with every use of said digital work; and
c) control means (21) for refusing the use of said digital work (DW) if said updated usage right information indicates that the usage right has been exercised characterized in that d) said updating means (22) is arranged to change a hidden information (KLK) stored in a hidden channel and used for encrypting or verifying said usage right information, when said usage right information has changed.
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Specification