METHODS FOR IMPLEMENTING AND OBFUSCATING A CRYPTOGRAPHIC ALGORITHM HAVING A GIVEN SECRET KEY

The present invention relates to a method for implementing a cryptographic algorithm having a given secret key comprising the execution by data processing means (11a) of an equipment (10a) of a code implementing said cryptographic algorithm stored on data storage means (12a) of the equipment (10a), the method being characterized in that at least one so-called obfuscated part of said code parameterized with said secret key uses only one so-called cmov instruction, which is a conditional move instruction in a first operand of the instruction of a second operand of the instruction, with at least one occurrence of said cmov instruction in said obfuscated part of the code being dummy.