Tamper-resistant semiconductor device comprising: - a semiconductor substrate comprising an electronic circuit arranged on a first side thereof; an electrically-conductive protection layer (50, 50a, 50b) arranged on a second side of the semiconductor substrate opposite to the first side; - at least three through-substrate electrically-conductive connections extending from the first side of the semiconductor substrate into the semiconductor substrate and in electrical contact with the electrically-conductive protection layer (50, 50a, 50b) on the second side of the semiconductor substrate; - a security circuit being arranged on the first side connected to the through-substrate electrically-conductive connections and being arranged i) for measuring at least two resistance values (R12, R23, R34, R14, R13, R24) of the electrically-conductive protection layer (50, 50a, 50b) through the through-substrate electrically-conductive connections to provide a security code, and ii) for comparing the security code (R12, R23, R34, R14, R13, R24) with a reference code, characterized in that the semiconductor substrate comprises an SOI substrate, the SOI substrate comprising a semiconductor substrate layer, a buried-oxide layer provided on the semiconductor substrate layer, and an active layer provided on the buried-oxide layer, the active layer being located at the first side of the semiconductor substrate and the semiconductor substrate layer being located at the second side of the semiconductor substrate, the electronic circuit being provided in the active layer, wherein the through- substrate connections extend from the first side through the active layer and the buried-oxide layer to the semiconductor substrate layer, and wherein the electrically-conductive protection layer (50, 50a, 50b) is provided on the semiconductor substrate layer at the second side of the semiconductor substrate. - a semiconductor substrate comprising an electronic circuit arranged on a first side thereof; an electrically-conductive protection layer (50, 50a, 50b) arranged on a second side of the semiconductor substrate opposite to the first side; - at least three through-substrate electrically-conductive connections extending from the first side of the semiconductor substrate into the semiconductor substrate and in electrical contact with the electrically-conductive protection layer (50, 50a, 50b) on the second side of the semiconductor substrate; - a security circuit being arranged on the first side connected to the through-substrate electrically-conductive connections and being arranged i) for measuring at least two resistance values (R12, R23, R34, R14, R13, R24) of the electrically-conductive protection layer (50, 50a, 50b) through the through-substrate electrically-conductive connections to provide a security code, and ii) for comparing the security code (R12, R23, R34, R14, R13, R24) with a reference code, i) for measuring at least two resistance values (R12, R23, R34, R14, R13, R24) of the electrically-conductive protection layer (50, 50a, 50b) through the through-substrate electrically-conductive connections to provide a security code, and ii) for comparing the security code (R12, R23, R34, R14, R13, R24) with a reference code,