Method for communicating entitlement data from a server, related server, client systems and computer program product
First Claim
1. A method of communicating a set of entitlement data from a server to at least one client, the set of entitlement data including a set of predicates representative of entitlement of the at least one client to access corresponding content data stored on the server, comprising the steps of:
- determining a set of keys each corresponding to a predicate in said set of predicates, wherein each key in said set of keys is determined by varying said key and calculating a result of a non-invertible function being applied to a bit until said result is equal to the corresponding predicate;
causing said server and said at least one client to share said non-invertible function and one of said set of keys and said bit string; and
transmitting from said server to said at least one client the other remaining one of said set of keys and said selected bit string that is not shared with said at least one client.
1 Assignment
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Accused Products
Abstract
A server communicates a set of entitlement data representative of the entitlement of a client to access corresponding contents data by using a set of keys and a non-invertible cryptographic function. The cryptographic function is applied to a set of candidate bit strings using the set of keys to find a selected bit string that produces the set of entitlement data as a result of the application of the non-invertible cryptographic function by using the keys in the set. The server and the client share the cryptographic function as well as the set of keys (or the selected bit string). The server transmits to the client the selected bit string (or the set of keys). In either case, the client is thus in a position to apply the cryptographic function to the selected string of bits by using the set of keys, thereby reconstructing the set of entitlement data.
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Citations
17 Claims
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1. A method of communicating a set of entitlement data from a server to at least one client, the set of entitlement data including a set of predicates representative of entitlement of the at least one client to access corresponding content data stored on the server, comprising the steps of:
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determining a set of keys each corresponding to a predicate in said set of predicates, wherein each key in said set of keys is determined by varying said key and calculating a result of a non-invertible function being applied to a bit until said result is equal to the corresponding predicate; causing said server and said at least one client to share said non-invertible function and one of said set of keys and said bit string; and transmitting from said server to said at least one client the other remaining one of said set of keys and said selected bit string that is not shared with said at least one client. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification