FIELD: information technologies.
SUBSTANCE: method includes the following stages: receipt of the first control message (ECM1), containing at least one control word (CW) and time score (TS); receipt of the second control message (ECM2), following the first control message (ECM1), besides, the second control message contains at least one control word (CW) and time score (TS); detection of duration of time period, corresponding to difference between time scores (TS) of two serial messages ECM1, ECM2; increasing counter of errors (CE) in case specified duration of time period is less than previously set duration (CP); reducing counter of errors (CE) in case specified duration of time period equals or exceeds specified previously set duration; return of control word (CW) into module of processing (STB) as waiting time expires, which depends on value of counter of errors (CE).
EFFECT: prevention of access to coded content in case of fraudulent use of decoders.
16 cl, 6 dwg
