Optimizing the power used in an integrated circuit. According to the invention, the microcontroller also includes: means to vary the supply voltage of the efficient data processing part, the said means being able to secure the said confidential data against current attacks. The slide module includes a first slide member fixed to the first body, a second slide member fixed to the second body, and a guide unit provided between the first slide member and the second slide member to guide the first slide member in sliding movement in longitudinal and transverse directions. Items in each of the first and second grids may be moved between the two grids to quickly change the assigned state of moved items. Finally, the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of no greater than about 20 Shore C. Accurate serial number inherent to the device can be acquired and device authentication can be made.