A device (CD) is intended for controlling authenticity of a code received with a message by an electronic device (ED2) and resulting from application to this message of a bijective algorithm with at least one predetermined key. This device (CD) has i) a first computation means (CM1) arranged for applying partly this bijective algorithm with this predetermined key, from a starting step to a chosen intermediate step, to the received message, in order to get a first result, ii) a second computation means (CM2) arranged for applying partly in a reverse manner the bijective algorithm with the predetermined key, from an ending step to this chosen intermediate step, to the received code while using the received message, in order to get a second result, and iii) a comparison means (CM3) arranged for comparing these first and second results and for outputting an information representative of the authenticity of the received code when the first and second results are identical.