Before understanding the chip method, we need to know what is a chip, there are many definitions of chip decryption on the Internet, in fact, chip decryption is to change the encrypted chip into a non-encrypted chip by means of semiconductor reverse development technology, and then use the programmer to read the program out.
The conditions that the chip has to have are.
First, you have some knowledge of how to turn an encrypted chip into a non-encrypted.
Second, you must have the tools to read the program, some people may say, it is just a programmer. Yes, it is a programmer, but not all programmers are equipped with readable functions. This is why we sometimes develop a readable programmer in order to decrypt a chip. With a readable programmer, then we will talk about some of the methods that chips often have.
1, FIB recovery encryption fuse method.
This method applies to many chips with fuse encryption, the most representative chip is TI’s MSP430 decryption method, because the MSP430 encryption to burn the fuse, then as long as the fuse can be restored on, it becomes a non-encrypted chip, such as MSP430F1101A decryption, MSP430F149 decryption, MSP430F425 decryption etc. General decryption companies use probes to achieve, the fuse bit connected, but also because they do not have too much decryption equipment, you need to hand over to other semiconductor line modification companies to modify the line, you can generally use the FIB (focused ion beam) equipment to connect the line on, or use special laser modification equipment to restore the line. These devices are currently available in many used devices in China and are also very cheap, and some powerful decryption companies have configured their own devices. This method is not a good method due to the need for equipment and consumables, but many chips need this method to be implemented if there is no better method.
2. Methods of modifying encryption lines.
The current market CPLD and DSP chip design is complex, encryption performance to be high, using the above method is difficult to do decryption, then you need to make the front analysis of the chip structure, and then find the encryption circuit, and then use the chip line modification equipment to make some changes to the chip line, so that the encryption circuit failure, so that the encrypted DSP or CPLD becomes a non-encrypted chip so that you can read out code. Such as TMS320LF2407A decryption, TMS320F28335 decryption, TMS320F2812 decryption is to use this method.