Abstract: A video source application in a video source device requests from a video hardware interface of the video source device status with respect to a link linking the video source device to an external video sink device, and supplements the status request with a first basis value to a symmetric ciphering/deciphering process. The video source application, upon receiving from the video hardware interface the requested status and a verification key, generated using said symmetric ciphering/deciphering process and employing the first basis value, verifies the correctness of the verification key to determine whether to trust said provided status. In like manner, the video source application requests from the video hardware interface a secret the video hardware interface uses to cipher video to be transmitted by the video hardware interface to the external video sink device. The secret request is supplemented with a second basis value to the symmetric ciphering/deciphering process.

Abstract: Protected content distribution is accomplished by a first entity generating a set of asymmetric key pairs, creating a plurality of sets of private keys by selecting a combination of private keys from the set of asymmetric key pairs for each created set, and distributing the sets of private keys to playback devices. A second entity produces protected content including encrypted content and a public key media key block, encrypts a symmetric content key with each public key in the set of asymmetric key pairs to form the public key media key block and encrypts a content title with the symmetric content key to form the encrypted content. A playback device stores one set of private keys, receives the protected content, and decrypts and plays the content title stored in the protected content when a selected one of the set of private keys stored by the playback device successfully decrypts the encrypted symmetric content key stored in the public key media key block of the received protected content.

Abstract: In a cryptographic system, a nonce is removed from a communication stream. The nonce is encrypted based on a shared secret. The encrypted nonce is inserted into the communication stream. The encrypted nonce is removed from the communication stream. The encrypted nonce is decrypted based on the shared secret formed by an authenticated key exchange. The decrypted nonce is inserted into the communication stream. The nonce may be an An value generated by a HDCP function. The authenticated key exchange may use Diffie-Hellman Key Exchange.

Abstract: A method and apparatus for automatically delivering data files, (e.g. television and movies) via a personalized channel to a user, that are based on a user's profile and viewing habits, are provided. A client receives meta-data broadcasts from a server system that includes descriptions of a plurality of data files currently being broadcasted or to be broadcast by the server system. In response to a content rating table that is based on a user's profile and viewing habits, a data file is automatically selected. The selected data file is displayed on a personalized channel on a display device to the user. The selected data file can be, for example, a currently broadcasting data file or a data file stored in a cache memory of the client. Thus, the user only needs to tune to his or her personalized channel to view personalized content.