| 摘要 |
The aim of the present invention is to propose a method to prevent the abusive use of conditional access data, in particular by means of clones of security modules whose security has been compromised. This aim is reached by a revocation method of security modules intended to receive security messages broadcasted to a plurality of security modules, said security modules comprising at least one personal key, this method comprising the steps, prior to revocation: division of the set of security modules into at least two groups, determination for each group of an asymmetrical key comprising a public key and a plurality of private keys, loading of one private key per security module, transmission of one security message per group, said message being encrypted by the public key of said group; revocation consisting in the following steps: sending to each member of the same group as the security module to be revoked, with the exception of the security module(s) to be revoked, of a new private key corresponding to the public key of another group, each private key being encrypted by the personal key of said security module.
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