Transponder comprising a resonant circuit, comprising an antenna and a capacitor, and at least one memory, wherein it comprises at least one contact zone for receiving a portion of human body, so that the positioning of a portion of human body on a contact zone modifies the electric circuit of the transponder, capable of switching from a first state in which it does not allow the memory to be read and/or written to a second state in which it allows the memory to be read and/or written when the resonant circuit of the transponder is contactlessly powered by a reader and in that it comprises an indicator which makes it possible to indicate that the positioning of a portion of human body on the contact zone of the transponder is or has been recognized.