Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.