Patent Document ID: 8646097
Application ID: 12383787

Base Claim:
1. A security module for an audio/video digital data processing unit for conditional access, said audio/video digital data being encrypted within an encoded data stream by control words, said security module comprising a processor programmed to: process a security message included within a control message stream and containing at least one cryptogram relative to a control word and one instruction relative to the control word; download at least two micro programs to the security module within said security messages; receive the security message and extract the cryptogram and the instruction; select one micro program among the micro programs according to a value of the instruction; execute the selected micro program with at least the extracted cryptogram as an entry variable of the selected micro program; in response to executing the selected micro program, calculate the control word; and transmit the calculated control word to a decoding device to decrypt the encrypted audio/video digital data; and a memory programmed to store said at least two micro programs after being downloaded to the security module.

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Claim 4:
4. The security module according to claim 1 , comprising a cryptographic module wherein the cryptogram includes first and second parts, the first part acting on the micro program selected by the instruction and the second part acting on the cryptographic module receiving the result obtained by the selected micro program for calculating the control word.