| 摘要 |
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, which may be unencrypted, is verified by using a hidden information which is changed at every change of the usage right information. The hidden information may be a checksum of a data block containing the usage right information, or other encoding that may detect a change to the stored data block. 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. |
