Patent ID: 7836300

Claim:
A semiconductor integrated circuit, comprising: a monolithic circuit for decryption of encrypted broadcast signals, the monolithic circuit comprising: an input interface structured to receive the encrypted broadcast signals, to receive broadcast encrypted common keys, and to receive encrypted broadcast control data having encrypted control signals, and an output interface for output of decrypted broadcast signals; a processing unit arranged to receive the encrypted broadcast signals via the input interface, to decrypt the encrypted broadcast signals in accordance with decrypted control signals, and to provide decrypted broadcast signals to the output interface; a first decryption circuit arranged to receive encrypted control signals from the input interface, to decrypt the control signals in accordance with a decrypted common key from a dedicated common key store in the integrated circuit, and to output the decrypted control signals to the processing unit, the common key store structured to store a plurality of decrypted common keys in association with a respective identifier corresponding to each broadcast signal; and a second decryption circuit arranged to receive the common key in encrypted form from the input interface and to decrypt the common key in accordance with a secret key from a secret key store in the integrated circuit and to store the decrypted common key in the decrypted common key store, the secret key being unique to the monolithic circuit and being not accessible from outside the monolithic circuit; the monolithic circuit structured so that the only route to placing a common key in the common key store is to receive by broadcast the common key in encrypted form for decryption in accordance with the secret key and provide the common key to the common key store over an internal bus, the common key store receiving and storing a plurality of decrypted common keys that provide different levels of access to the broadcast signals, and the only route to providing the control signals to the processing unit is to input them in encrypted form for decryption in accordance with the common key.