Generally speaking, there is an encryption authentication chip on the PCB, plus some simple circuits, and at the same time loading anti-theft algorithms to prevent the internal information of the chip from being stolen, it is called chip encryption technology. At this time, when the encryption lock bit is locked during programming, the ordinary programmer cannot directly read the program in the chip, which plays a protective role.
According to different data encryption schemes and usage methods, it can be divided into two types of encryption chips
One is the authentication type encryption chip, and its advantage is the security of the encryption chip service platform, the unified algorithm, and the ease of use. Disadvantages The overall safety factor is low, and the protection of the main control MCU is weak. It has been confirmed that there are obvious security vulnerabilities. The encryption chip can be cracked concisely by attacking the MCU.
The other is the encryption chip of the smart chip service platform, which uses algorithms and data migration solutions. Part of the program and part of the data of the main control MCU are transplanted to the encryption chip to run. The encryption chip is used to complete the missing functions of the MCU during operation, while ensuring the absolute safety of some programs and ensuring the safety of the entire product.
What are the chip encryption technologies
1. Grind the chip, use fine sandpaper to grind off the model specifications on the chip. It is more useful for unpopular chips. For common chips, you only need to guess the general function, check the grounding of the pin and connect the power supply, and it is easy to compare the real chip.
2. Sealing glue, the stone-like glue (such as sticking steel, ceramics) after solidification will cover all the components on the PCB. At the same time, the internal wiring is disturbed and twisted together with thin enameled wires, so that the flying wires are easy to break when the glue is removed, and the connection is not known. Matters needing attention The glue must not be corrosive, and the temperature rise of the enclosed area f is not large.
3. Porting part of the program in the CPU or software to the encryption chip, making the program incomplete, and it can run normally only with the cooperation of the encryption chip. Provide DES, 3DES encryption and decryption functions.
4. Bare chip, can't see the model specification and don't know the wiring. At the same time, the function of the chip is not easy to guess. Put other things in the vinyl, such as small ICs, resistors, etc.
5. Connect a resistance of 60 ohms or more in series on the signal line with low current (to make the on-off gear of the multimeter not sound), which will increase a lot of trouble when using the multimeter to measure the connection relationship.
5. Connect a resistor above 60 ohms in series on the power line with a small amount of current (to keep the digital multimeter on and off), which will increase the inconvenience when using the digital multimeter to test the connection.
6. Use some small components with unpopular code names to participate in signal processing, such as small chip capacitors, TO-XX diodes, small chips with three to six pins, etc., which increase the difficulty of finding the true function of the component.
7. Address or data line cross (except RAM, the corresponding cross is required in the software), which makes it impossible to draw inferences about the side connection relationship and increase the difficulty of operation.
8. PCB selects buried via and blind via technology, so that the via is hidden in the board. This approach has a higher cost and is suitable for high-end products.
9. Use other special supporting equipment, such as customized LCD screen, customized transformer, SIM card, encrypted hard disk, etc.