Patent ID: 7248694

Claim:
A method for providing a receiver subsystem with access via a clearing house subsystem to a broadcast content item broadcast from a content provider subsystem, the method comprising: in the content provider subsystem, encrypting the broadcast content item based on a content key to produce an encrypted content item, generating a blocking nonce corresponding to the content key, transmitting the content key and the blocking nonce to the clearing house subsystem, and transmitting the encrypted content item and the blocking nonce to the receiver subsystem; in the clearing house subsystem, receiving the content key and the blocking nonce from the content provider subsystem, receiving a public key of a public-private key pair of the receiver subsystem, and, in response to a request for access to the broadcast content item, encrypting the content key based on the public key to produce a public key encrypted content key, encrypting the public key encrypted content key based on the blocking nonce to produce a double encrypted content key, and transmitting the double encrypted content key to the receiver subsystem; and, in the receiver subsystem, receiving the double encrypted content key from the clearing house subsystem, receiving the encrypted content item and the blocking nonce from the content provider subsystem, decrypting the double encrypted content key based on the blocking nonce to recover the public key encrypted content key, decrypting the public key encrypted content key based on a private key of the public-private key pair to recover the content key, and decrypting the encrypted content item based on the content key to recover the requested broadcast content item.