Magnetic detection of back-side layer

The invention relates to an integrated circuit comprising a substrate having a first side and a second opposing side. An electronic circuit (EC) is provided at the first side (S1) of the substrate, wherein the electronic circuit (EC) comprises at least one magnetic field sensor (Snsr, Snsr1, Snsr2, Snsr3, Snsr4). The integrated circuit further comprises a magnetizable region (MR) provided on the second side (S1) of the substrate (SUB) by using a wafer-level type deposition processing step. The magnetic moment of the magnetizable region (MR) is configurable for generating a magnetic field (H1, H2) detectable at the location of the at least one magnetic field sensor (Snsr, Snsr1, Snsr2, Snsr3, Snsr4). The integrated circuit constitutes a very simple construction and enables a strongly miniaturized solution which is, because of its reduced dimensions well suitable for being used in bank cards. An attempt to remove the integrated circuit according to the invention from its environment (e.g. a bank card) may result in the magnetizable region (MR) getting damaged (partially removed) or even completely removed. The invention provides a first level of security against external attack. Embodiments of the invention provide higher security levels. Various magnetic field sensors are illustrated which may be advantageously integrated in the integrated circuit. The invention also relates to a card provided with such integrated circuit. The card in accordance with the invention is more secure. The invention further relates to a method of initializing such integrated circuit and a method of checking the authenticity of such integrated circuit.