Crack MCU software file, as we mentioned above, MCU cracker can use laser scanning to read the status of transistors and the 1st step of reverse engineering microcontroller is decapsulate the silicon package. And just MCU Cracker expected, laser can scan the P and N type transistor’s source in the MCU memorizer as well as the photocurrent generated from the drain electrode, un-transparent metal wire can be use to treat the lowest photocurrent.
The result of laser scanning can see the photocurrent in the inverse switch status of SRAM unit obviously which can be used to assure the MCU memorizer status after Cracking it. In order to explain the result for the purpose of pursuit more proper scanning parameters, use DIODE-2D present the laser impulse to two dimension of reversor.
The length of narrow channel is assumed to be 1 micron, laser radiation strength is 1.104W/cm2. Other parameters, such as mixed density, P and N channel depth, use the standard 1 micron N type base CMOS technology parameter of MCU software Cracking.
MCU Cracker has simulate the two status of reversor, the laser with different wavelength on the various locations, their relationship with the power supply current can reveal that the current of transistor in the turn off exposure status could be much bigger than the current in the turn on exposure status. Turn up the shutdown transistor channel can increase the total current and its increasing amount is much bigger than the slightly decrease the open channel resistor slight.