FIELD: radio engineering, communication.
SUBSTANCE: invention relates to means of detecting illegal use of a processing device of a security system, used to descramble various media data distributed over multiple corresponding channels. The method includes counting new messages ECMj,c, received by the processing device of the security systems for channels, other than channel i, after the last received message ECMi,p; verifying that the message ECMi,c was received during said time interval by verifying that the number of new messages ECMj,c, received for channels other than i, reaches or exceeds a given threshold greater than two; increasing the counter Kchi by the given value each time when after verification a message ECMi,c is received during a given time interval, immediately after a message ECMi,p, otherwise the counter Kchi is reset to the initial value; detecting illegal use once the counter Kchi reaches said threshold.
EFFECT: reducing the probability of illegal use of a processing device.
10 cl, 3 dwg
