Recently, a PLC controller circuit was reversely developed and copied. The primary chip model is the STM32F100 series chip. After the IC unlocked, the sample is sent to the customer test. After two days of customer aging test, the various states are entirely normal. After completing the chip decryption program with our company, our company sends the program. A seemingly ordinary STM32F100 crack is done.
After one month, the customer once again sent a call to our company. The feedback said that after five working days, the chip could not work usually. All the boards are this one problem. The chip can be burned again and can be used also.
Our technical engineer, in response to customer response problems, came up with a solution. The original designer of this board added a time limit to this soft encryption in the circuit.
From this technical point of view, our company engineers again disassembled the program, found out the original encryption location, successfully solved the problem, and the chip decryption was utterly successful.