SECURITY METHOD, DECODING METHOD, DATA MEDIUM AND TERMINAL FOR SECURITY METHOD Russian patent published in 2014 - IPC H04N7/167 

FIELD: physics, computer engineering.

SUBSTANCE: method of securing transmission of multimedia content or a control word between a security processor and a terminal comprises steps of pre-recording multiple secret codes $$C_i^{-1}$$ into a terminal, each secret code $$C_i^{-1}$$ enabling to decode the multimedia content or control word encoded by a corresponding session key SK_i, obtained by encoding a SK_root key using a parameter P_i, wherein one of the parameters P_i is a parameter P_c; the terminal receives (122) the parameter P_c in a message, also containing multimedia content or a control word to be decoded by the security processor, and from the set of recorded secret codes, a secret code $$C_c^{-1}$$ is selected (132) to be used as a function of the parameter P_c or another parameter contained in the same message.

EFFECT: improved security.

11 cl, 6 dwg