06785815 is referenced by 371 patents and cites 7 patents.

Systems and methods are provided for protecting and managing electronic data signals that are registered in accordance with a predefined encoding scheme, while allowing access to unregistered data signals. In one embodiment a relatively hard-to-remove, easy-to-detect, strong watermark is inserted in a data signal. The data signal is divided into a sequence of blocks, and a digital signature for each block is embedded in the signal via a watermark. The data signal is then stored and distributed on, e.g., a compact disc, a DVD, or the like. When a user attempts to access or use a portion of the data signal, the signal is checked for the presence of a watermark containing the digital signature for the desired portion of the signal. If the watermark is found, the digital signature is extracted and used to verify the authenticity of the desired portion of the signal. If the signature-containing watermark is not found, the signal is checked for the presence of the strong watermark. If the strong watermark is found, further use of the signal is inhibited, as the presence of the strong watermark, in combination with the absence or corruption of the signature-containing watermark, provides evidence that the signal has been improperly modified. If, on the other hand, the strong mark is not found, further use of the data signal can be allowed, as the absence of the strong mark indicates that the data signal was never registered with the signature-containing watermark.

Title
Methods and systems for encoding and protecting data using digital signature and watermarking techniques
Application Number
9/588652
Publication Number
6785815 (B1)
Application Date
June 7, 2000
Publication Date
August 31, 2004
Inventor
Gilles Boccon Gibod
Los Altos
CA, US
Xavier Serret Avila
Santa Clara
CA, US
Agent
Finnegan Henderson Farabow Garrett & Dunner L
US
Assignee
InterTrust Technologies
CA, US
IPC
G06F 1/26
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