Patent ID: 8824685

Claim:
A method of identifying a receiver device from which pirated video decryption keys have been obtained, comprising: splitting a population of receiver devices into a compromised population and a non-compromised population N groups; detecting a pirated video decryption key in one or more of the N groups; aggregating the groups comprising those groups in which a pirated video decryption key was not detected into a non-compromised population group; isolating the non-compromised population group; organizing the compromised population of receiver devices into a plurality of N new groups, where one of the N new groups is the non-compromised population group and the remainder of the N new groups is the group or groups containing the pirated video decryption key divided into subgroups; associating the N new groups with a plurality of N decryption keys, where each of the N new groups is associated with one of a plurality of N decryption keys; causing the plurality of N decryption keys to be obtained by their associated N new groups of receiver devices by direct delivery or by derivation at the receiver devices; and encrypting one or more entitlement control messages (ECMs) using one of a plurality of N periodic keys so as to produce N sequences of content keys respectively associated with the N new groups in order to segregate the receiver devices by virtue of their use of multiple decryption keys to decrypt content.