Intertrust Technologies Corporation

Xavier Serret-Avila

Gilles Boccon-Gibod

Stephen P Weeks

Systems and methods are disclosed for enabling a recipient of a cryptographically-signed electronic communication to verify the authenticity of the communication on-the-fly using a signed chain of check values, the chain being constructed from the original content of the communication, and each check value in the chain being at least partially dependent on the signed root of the chain and a portion of the communication. Fault tolerance can be provided by including error-check values in the communication that enable a decoding device to maintain the chain's security in the face of communication errors. In one embodiment, systems and methods are provided for enabling secure quasi-random access to a content file by constructing a hierarchy of hash values from the file, the hierarchy deriving its security in a manner similar to that used by the above-described chain. The hierarchy culminates with a signed hash that can be used to verify the integrity of other hash values in the hierarchy, and these other hash values can, in turn, be used to efficiently verify the authenticity of arbitrary portions of the content file.

Systems and methods for authenticating and protecting the integrity of data streams and other data

The present invention provides systems and methods for making efficient trust management decisions. A trust management engine is provided that processes requests for system resources, authorizations or certificates, and the identity of one or more root authorities that are ultimately responsible for granting or denying the requests. To determine whether a request should be granted, the trust management engine identifies a set principals from whom authorization may flow, and interprets each of the certificates as a function of the state of one or more of the principals. The processing logic iteratively evaluates the functions represented by the certificates, updates the states of the principals, and repeats this process until a reliable determination can be made as to whether the request should be granted or denied. The certificates may be evaluated until the state of the root authority indicates that the request should be granted, or until further evaluation of the certificates is ineffective in changing the state of the principals.

Trust management systems and methods

Systems and methods are provided for determining a presence of a watermark in electronic data. In certain embodiments, a plurality of keys is generated, and a plurality of payloads are retrieved from electronic data using the keys. A statistical indicia of randomness is generated based on the payloads, and the presence of a watermark is determined when the indicia is below a threshold.

Methods and systems for encoding and protecting data using digital signature and watermarking techniques

Trust-management systems and methods

Systems and methods are provided for protecting and managing electronic data signals. In one embodiment a strong watermark is inserted in a data signal that is divided into a sequence of blocks, and a digital signature for each block is embedded in the signal via a watermark. The signal is then stored and distributed. When attempts are made to use or access the 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 not found, the signal is checked for the presence of the strong watermark, which if found causes the system to inhibit further use of the signal, and if not found further use of the signal is allowed.

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.

Growing community of inventors

Santa Clara, CA, United States of America

Xavier Serret-Avila