A method for the performance of a function by a microcircuit, includes:at least one step of determining (205) whether an anomaly is detected or whether the operation of the microcircuit is normal;when it is determined that an anomaly is detected, a step of performing (210) a protection function;when it is determined that the operation of the microcircuit is normal, a step of performing (215) a decoy function simulating the protection function by being perceptible, from the outside of the microcircuit, in a manner more or less identical to the protection function;the method being characterized in that it includes an interruption (250) of the performance of the decoy function by a timer.