Control method and device for controlling code authenticity by applying bijective algorithm to messages

摘要

The device (CD) controls the authenticity of the code, which is the result of applying to the message a bijection algorithm using at least one predetermined key received with the message by the electronic device (ED2). Intended. The device (CD) (i) partially applies the bijection algorithm to the received message using the predetermined key from the start step to the selected intermediate step to obtain a first result. And (ii) using the received message to obtain a second result, while simultaneously using the received code from the ending step to Up to this selected intermediate step, a second calculation means (CM2) configured to partially apply the bijection algorithm in a reverse manner using a predetermined key; and (iii) these first and Comparing means (CM3) for comparing the second result and outputting the information indicating the authenticity of the received code when the first and second results are the same.