Introduction to tools
CRC is a data error checking technology, which can ensure that the data originally written to the image file is consistent with the data used from the image file.
CRC32 means that 32-bit is used to save error checking information. When creating an image file, the details of CRC32 will be embedded in the file to ensure that it can be detected whether it is damaged when restoring the file to disk.
common problem
1. What is the output length of CRC-32?
The length of the check value is fixed to 8 characters, so the function that generates it is occasionally used as a hash function.
2. What does CRC32 stand for?
It represents a 32-bit cyclic redundancy check.
3. What are the differences between CRC-8, CRC-16, CRC-32 and CRC-64?
The choice of generating polynomials is the most important part of CRC algorithm. Polynomials must be selected to maximize error detection capabilities while minimizing the overall conflict probability. The most important attribute of a polynomial is its length (the maximum degree (exponent) of any term in the polynomial+1), because it directly affects the length of the calculated check value. The most commonly used polynomial lengths are:
- 9-bit (CRC-8)
- 17 bit (CRC-16)
- 33 bits (CRC-32)
- 65 bit (CRC-64)
4. How does CRC32 implement verification?
Cyclic redundancy check (CRC) is an error detection code used to detect data corruption. When sending data, a short checksum is generated according to the data content and sent together with the data. When receiving data, the checksum is generated again and compared with the sent checksum. If both are equal, there is no data corruption. The CRC-32 algorithm itself converts variable length strings into 8-character strings.
