FIELD: physics, computer engineering.
SUBSTANCE: invention relates to information decryption methods. The method comprises steps of, in response to the absence in any of the terminals of one or more control words CWc for decrypting one or more multimedia content cryptoperiods, transmitting through said terminal to a control word server a request containing a cryptogram(s) of said one or more absent control words, and in response, transmitting by the control word server to said terminal said one or more absent control words, wherein the control word server selectively determines for each terminal the number of additional control words CWs intended for transmission to the terminal depending on the probability of compromising the protection of said additional control words, and besides the absent control words CWc, transmitting to said terminal said determined number of additional control words CWs, which enables the terminal to decrypt additional multimedia content cryptoperiods in addition to cryptoperiods decrypted using the requested absent control words CWc.
EFFECT: ensuring secure transmission of control words.
10 cl, 6 dwg
