Control method and device for controlling authenticity of codes resulting from application of a bijective algorithm to messages

A control device (CD) for controlling authenticity of a code received with a message by a first electronic device (ED2) from a second electronic device, said code resulting from application of a bijective algorithm to said message using at least one predetermined key, the control device comprising i) receiving means for receiving, by the first electronic device, the message and the code from a second electronic device;

• ii) a first computation means (CM1) arranged for applying partly said bijective algorithm to said received message, using said predetermined key, from a starting step to a chosen intermediate step, in order to determine a first result;
• iii) a second computation means (CM2) arranged for applying partly in a reverse manner said bijective algorithm with said predetermined key, from an ending step to said chosen intermediate step, to said received code while using said received message, in order to determine a second result;
• iv) a comparison means (CM3) arranged for comparing said first and second results;
• and v) an outputting means for outputting an information representative of the authenticity of said received code when said first and second results are identical.

An electronic device (ED2), comprising a control device (CD) for controlling authenticity of a code received with a message by a first electronic device (ED2) from a second electronic device, said code resulting from application of a bijective algorithm to said message using at least one predetermined key, the control device having i) receiving means for receiving, by the first electronic device, the message and the code from a second electronic device;

• ii) a first computation means (CM1) arranged for applying partly said bijective algorithm to said received message, using said predetermined key, from a starting step to a chosen intermediate step in order to determine a first result;
• iii) a second computation means (CM2) arranged for applying partly in a reverse manner said bijective algorithm with said predetermined key, from an ending step to said chosen intermediate step, to said received code while using said received message, in order to determine a second result;
• iv) a comparison means (CM3) arranged for comparing said first and second results;
• and v) an outputting means for outputting an information representative of the authenticity of said received code when said first and second results are identical.