What's the cracking process of chip decryption?

  1. Chip Information Collection
    • Determine the Chip Model
      • This is the fundamental step of chip decryption. The specific model of the chip is determined by observing the markings on the chip's surface, such as the manufacturer's logo and the model - code of the chip. For example, for some well - known chip manufacturers like Intel and Texas Instruments, their chip model markings usually follow certain naming rules.
      • Professional electronic equipment testing tools, such as a chip tester, can also be used to obtain the electrical characteristic parameters of the chip, thus assisting in determining the chip model. These parameters include the chip's operating voltage, operating frequency, the number of input/output pins, etc.
    • Collect Chip Documentation
      • Look for the official documents provided by the chip manufacturer, such as the data sheet and user manual. These documents contain detailed technical specifications of the chip, such as the internal architecture, functional modules, instruction set and other important information.
      • Relevant materials such as the usage experience of the chip shared by other engineers, possible vulnerabilities or existing decryption ideas can also be collected through electronic technology forums, professional technology websites and other channels.
  2. Chip Decapsulation (for Encapsulated Chips)
    • Chemical Decapsulation
      • If the chip is in a plastic - encapsulated or other encapsulated form, it needs to be decapsulated first. Chemical decapsulation is one of the commonly used methods. Chemical reagents are used to dissolve the encapsulation material of the chip. For example, for an epoxy - encapsulated chip, a specific acidic or alkaline chemical solution can be used to corrode the encapsulation material under appropriate temperature and time conditions to expose the internal wafer of the chip.
      • This process requires strict control of the concentration of chemical reagents, reaction time and temperature to avoid damage to the internal structure of the chip. Because if the chemical reagent over - reacts, it may corrode the metal wires or active devices of the chip, resulting in the chip being unable to work properly or the decryption failing.
    • Laser Decapsulation
      • Laser decapsulation is a more precise decapsulation method. The encapsulation material of the chip is selectively removed by a high - energy laser beam. The advantage of this method is that the location and depth of decapsulation can be precisely controlled, reducing accidental damage to the internal structure of the chip.
      • However, laser decapsulation equipment is usually expensive, and the technical requirements for operators are relatively high. Professional training is required to operate it accurately.
  3. Chip Internal Circuit Imaging and Analysis
    • Optical Microscope Observation
      • The opened - up chip is observed with an optical microscope to see the general layout inside the chip, such as the position of each functional module of the chip, the pattern of the chip's metal wires, etc. By adjusting the magnification of the microscope, different - level detail information can be obtained.
      • However, the resolution of the optical microscope is limited, and it may not provide a clear - enough image for some tiny device structures inside the chip, such as nanometer - level transistors.
    • Electron Microscope Analysis
      • A scanning electron microscope (SEM) can provide a higher - resolution image of the internal part of the chip. It generates a high - definition image of the chip's surface by emitting an electron beam and detecting the reflected electrons, and can clearly show the microscopic structure inside the chip, such as the shape and size of transistors and the connection relationships between them.
      • Element analysis can also be carried out with an electron microscope. For example, through the energy - dispersive spectrometer (EDS) function, the material composition of different regions inside the chip can be determined, which is very helpful for understanding the chip's manufacturing process and possible weak links.
    • Circuit Extraction and Reconstruction
      • After obtaining a clear image of the internal part of the chip, circuit extraction is carried out. Through specialized circuit - extraction software, combined with manual analysis, each circuit element inside the chip, such as transistors, capacitors, resistors, etc., is identified, and their connection relationships are determined.
      • Then, according to the extracted circuit information, the circuit is reconstructed, and the internal circuit of the chip is represented in the form of a schematic diagram or a layout diagram. This process may need to be compared and verified repeatedly to ensure that the reconstructed circuit is consistent with the actual internal circuit of the chip.
  4. Cryptanalysis and Cracking (for Encrypted Chips)
    • Determine the Type of Encryption Algorithm
      • By studying the chip's documentation and analyzing the chip's internal circuit, an attempt is made to determine the type of encryption algorithm adopted by the chip. Common encryption algorithms include symmetric encryption algorithms (such as AES, DES, etc.) and asymmetric encryption algorithms (such as RSA, etc.).
      • Observe whether there are specific encryption modules inside the chip, such as an encryption engine, a key - storage unit, etc. The structure and working mode of these modules can provide clues for judging the type of encryption algorithm.
    • Key Extraction or Cracking
      • If a simple key - storage method such as plain - text storage in a specific storage area of the chip is adopted, an attempt can be made to find the key - storage location through the analysis of the chip's internal circuit and then extract the key.
      • For chips with complex encryption algorithms and key - protection mechanisms, cryptanalysis techniques such as differential cryptanalysis and linear cryptanalysis may be required. By analyzing the mathematical characteristics of the encryption algorithm, possible cracking approaches are sought. This is usually a complex and time - consuming process that requires in - depth knowledge of cryptography and powerful computing resources.
    • Verify the Cracking Results
      • After obtaining the possible key or cracking method, verification is needed. The data stored in the chip is decrypted using the extracted key, or the encryption/decryption process of the chip is simulated using the cracked algorithm, and the results are compared with the known correct results.
      • If the decrypted results match the expectations, it means the cracking is successful; otherwise, the cracking process needs to be re - examined to check for wrong assumptions or analysis steps.
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