Abstract: A method to bind the use of a digital audio/video service data receiver to a network on which at least one services provider broadcasts access controlled and free digital audio/video services streams, the method having the steps: receiving by the receiver a periodic signal transmitted by a conditional access system server via the network, said periodic signal being processed by a run time software embedded in the receiver to check legitimacy of the network; displaying services available on the network only if said run time software recognizes the periodic signal as indicating network legitimacy; and checking operability of the run time software and if necessary taking actions to enforce limitation of using the receiver on the network checked as legitimate. The invention further discloses a receiver bound to a specific network configured to perform the method.

Abstract: A method to bind the use of a digital audio/video service data receiver to a network on which at least one services provider broadcasts access controlled and free digital audio/video services streams, the method having the steps: receiving by the receiver a periodic signal transmitted by a conditional access system server via the network, said periodic signal being processed by a run time software embedded in the receiver to check legitimacy of the network; displaying services available on the network only if said run time software recognizes the periodic signal as indicating network legitimacy; and checking operability of the run time software and if necessary taking actions to enforce limitation of using the receiver on the network checked as legitimate. The invention further discloses a receiver bound to a specific network configured to perform the method.

Abstract: A method to fight against cloning attacks is disclosed. In an initialization phase, the user unit sends to the server a request comprising a unique identifier of the user unit, check data, an initial payload key and a request instruction encrypted with a payload key retrieved from a memory of the user unit. Each time the server receives a request; the request instruction is decrypted by a payload key retrieved from a memory according to the unique identifier of the user unit. The server then generates a derivation key to be used by the user unit to compute a new payload key and checks in the next incoming request from the same user unit if the payload key is an expected one. The server detects cloning attacks thanks to a status parameter at decryption of the request instruction with the expected payload key.

Abstract: A method to prevent, detect and fight against cloning attacks by using payload keys to encrypt request and response messages exchanged between user units and server. In an initialization phase, the user unit generates locally an initial payload key and sends to the server in a secure way a request comprising a unique identifier of the user unit, check data, the initial payload key and a request instruction encrypted with a payload key retrieved from the memory of the user unit. Each time the server receives a request from a user unit; it will retrieve the payload key by searching in its memory according to the unique identifier of the user unit. The obtained payload key is then used to decrypt the request instruction. The server then generates a derivation key as response key which will be used by the user unit to compute a new payload key.