ShenZhen Hao Qi Core Technology Analysis: What are the techniques for chip decryption?

Tip 1: In order to prevent unauthorized access or copying of the on-chip programs of the microcontroller, most microcontrollers have encrypted lock bits or encrypted bytes to protect the on-chip programs. In fact, such protection measures are very fragile and can easily be crack. With the help of special equipment or self-made equipment, the MCU attacker can extract key information from the chip and obtain the internal program of the MCU by using the loopholes or software defects in the design of the MCU chip and through various technical means, so as to decrypt the MCU ic.

Tip 2: There are loopholes in the production process, use some programmers to locate the inserted bytes, and find out whether there are consecutive vacancies in the chip through a certain method, that is to say, to find the continuous FF FF bytes in the chip, the inserted bytes can be Execute the instruction that sends the program inside the chip to the outside, and then intercept it with the decrypted device, so that the program inside the chip is decrypted and completed.

Tip 3: Destroy the package, and then use semiconductor test equipment, microscopes and micro-positioners, but it takes hours or even weeks to complete the MCU ic decryption in a specialized laboratory.

Tip 4: Many chips have encryption loopholes when they are designed. Such chips can use loopholes to attack the chip to read the code in the memory, and use the loopholes in the chip code. If you can find the code like FF, you can insert the word. Section, to achieve MCU ic decryption.

Tip 5: Another possible attack method is to use equipment such as microscopes and laser cutting machines to find protective fuses, so as to find all signal lines connected to this part of the circuit. Due to a flawed design, simply cutting a single signal line from the protection fuse to other circuits disables the entire protection function. For some reason, this wire is so far away from the other wires that it is perfectly possible to cut this wire with a laser cutter without affecting adjacent wires. In this way, the contents of the program memory can be directly read out using a simple programmer.