Checksum is a way to validate the integrity of data. It is a simple calculation that helps detect errors in any kind of digital file, especially one that has been transferred or copied. To calculate checksum, the data needs to be processed through an algorithm. Once the calculations are complete, you can then compare to see if it matches with the original data. If there are any discrepancies, then there may have been some damage to the file along the way.
The checksum function is a widely used data integrity verification method. A checksum algorithm, for a given input string of bits, produces an associated value that depends on the sum of all the bits in the input string. The algorithm then converts this value to a larger fixed-length string of bits which acts as a digital fingerprint for the input bitstring. Checksums are typically used to differentiate between two otherwise identical files.