The invention relates to a method for securing the execution of a program by a processor, the program comprising a comparison instruction (S1) for comparing two data (D1, D2), followed by an operation of the program (SI2) which is selected as a function of a comparison result provided by the comparison instruction, the method comprising steps consisting in: before the execution of the comparison instruction, calculating in various ways comparison data representative of the equality of the data to be compared, after the execution of the comparison instruction, verifying whether the comparison data calculated are consistent with the fact that the operation is selected or not selected, and activating an error signal (ER) if the comparison data are mutually inconsistent or inconsistent with the result of the comparison.