1. Antifraud device ( 100 ) for validating a use of a real part of a body as an imprint-bearing substrate ( 150 ) and comprising: a control unit ( 106 ) configured to control other elements of the antifraud device ( 100 ), a sensor ( 102 ) configured to capture an image of an imprint carried by the substrate ( 150 ) placed on said sensor ( 102 ), a movement module ( 104 ), on which said sensor ( 102 ) is mounted, configured to apply pre-defined movement to said sensor ( 102 ), an analysis module ( 108 ) configured to receive data representing an image of an imprint ( 200 ) captured before a movement of said sensor ( 102 ) and an image of an imprint ( 200 ) captured after the movement of said sensor ( 102 ) and to analyse them, and, a decision-making module ( 110 ) configured to make a decision as to whether or not the substrate ( 150 ) is a real part of a body, from information transmitted by the analysis module ( 108 ).