Method for tracing traitor receivers in a broadcast encryption system
First Claim
1. A method for identifying disabling at least one traitor receiver with at least one associated unique, compromised decryption key in a broadcast encryption system, comprising:
- receiving a set of subsets derived from a tree defining leaves, each leaf representing a respective receiver;
identifying at least one traitor subset from the set of subsets as containing at least one leaf representing a candidate traitor receiver;
using the traitor subset, undertaking at least one of identifying disabling the traitor receiver; and
determining whether the traitor subset represents at least two traitor receiver candidates, and if so, dividing the traitor subset into two child sets, wherein the act of identifying or disabling includes encoding plural subsets of the set of subsets with a false key.
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Abstract
A method for tracing traitor receivers in a broadcast encryption system. The method includes using a false key to encode plural subsets representing receivers in the system. The subsets are derived from a tree using a Subset-Cover system, and the traitor receiver is associated with one or more compromised keys that have been obtained by a potentially cloned pirate receiver. Using a clone of the pirate receiver, the identity of the traitor receiver is determined, or the pirate receiver clones are rendered useless for decrypting data using the compromised key by generating an appropriate set of subsets.
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Citations
21 Claims
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1. A method for identifying disabling at least one traitor receiver with at least one associated unique, compromised decryption key in a broadcast encryption system, comprising:
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receiving a set of subsets derived from a tree defining leaves, each leaf representing a respective receiver; identifying at least one traitor subset from the set of subsets as containing at least one leaf representing a candidate traitor receiver; using the traitor subset, undertaking at least one of identifying disabling the traitor receiver; and determining whether the traitor subset represents at least two traitor receiver candidates, and if so, dividing the traitor subset into two child sets, wherein the act of identifying or disabling includes encoding plural subsets of the set of subsets with a false key. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A device, comprising:
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a computer readable medium, comprising; logic means for accessing a tree to generate a set of subsets of the tree, the tree including leaves representing at least one traitor device characterized by a compromised key; logic means for encrypting a false key j times and for encrypting a session key m-j times, wherein m is a number of subsets in the set of subsets; logic means responsive to the means for encrypting for identifying a traitor subset; and
logic means for using the traitor subset to identify or disable the traitor device. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A computer programmed with instructions to cause the computer to execute method acts including:
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using a false key to encode plural subsets representing stateless receivers, at least one traitor receiver of which is associated with at least one compromised key that has been obtained by at least one pirate receiver; and using the pirate receiver or a clone thereof, determining the identity of the traitor receiver, or rendering the pirate receiver or clone thereof useless for decrypting data using the compromised key. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification