Patent ID: 8885816

Claim:
A method for detecting illicit use of an electronic security processor used for descrambling of different multimedia content disseminated on several respective channels, said method comprising at said electronic security processor, receiving entitlement control messages, ECM i,t , to descramble a temporal sequence of cryptoperiods of a scrambled channel, i, each of said entitlement control messages ECM i,t comprising at least one cryptogram of a control word, CW i,t , for enabling a cryptoperiod, CP i,t , of said scrambled channel i to be descrambled, wherein i identifies said scrambled channel and index t is an order number, each time that said electronic security processor receives a new message, ECM i,c , checking that said new message, ECM i,c is received within a predetermined time slot immediately consecutive to a preceding message ECM i,p received by said electronic security processor for said channel i, wherein indices c and p are two specific values of said order number t, incrementing a counter Kch i by a predetermined step whenever, after verification, said message ECM i,c is received within a time slot immediately consecutive to said preceding message ECM i,p and, if not, resetting said counter Kch i to an initial value thereof, detecting an illicit use when said counter Kch i reaches a predetermined threshold; enumerating the new messages ECM j,c received b said electronic security processor for channels other than said scrambled channel i since the last message ECM i,p received; and verifying that said new message ECM i,c is received within the time slot in checking whether the number of new messages ECM i,c received for channels other than said scrambled channel i is greater than or equal to a predetermined threshold greater than two.