Patent ID: 8050406

Claim:
A receiver device that receives and decrypts digital television signals, comprising: a receiver that tunes and demodulates the television signal into a digital transport stream; a decrypter that decrypts the digital transport stream using a pair of decryption keys comprising an even key and an odd key, wherein the even and odd keys are alternately used by the decrypter for decryption during successive key epochs; a key table stored in a first secure persistent storage medium forming a part of the receiver device, the key table containing a library of a plurality of even keys and an associated plurality of odd keys forming key pairs that are indexed with a key identifier, wherein the library of key pairs can be accessed by an index to select a particular key pair from the library; where the index comprises a memory address; an authorization table stored in a second secure persistent storage medium forming a part of the receiver device, the authorization table containing a mapping in the form of a key index of a logical channel to a key pair identifier for each of a plurality of logical channels and further containing a service mask entry for each logical channel that determines authorization to access each logical channel and operational attributes associated with the logical channel and further containing a CPE operation mask that stores control attributes for the receiver device; where the mapping maps a each logical channel to a key index, and where there are more key indices than logical channels; at least one bouquet association table (BAT) having a unique identifier stored in the receiver device, that stores an association between a collection of logical channels and a service tier authorized for the receiver device; wherein, at least a portion of contents of the authorization table is received in a first encrypted private Entitlement Management Message (EMM) message in order to establish or change the mapping of a logical channel to a key pair identifier without need to change the library of key pairs, where the encrypted private EMM is devoid of any key associated with any logical channel in the library of key pairs but instead provides the key index associated with a logical channel so that the key index can be used to access a selected key from the library of key pairs; and means responsive to a user input for selecting one of the plurality of logical channels in the authorization table to identify a key index associated with the selected logical channel, and for further using the key index to select a key pair from the key table for use by the decrypter in decrypting the transport stream.