Camtech Checksums is a free utility for verifying the integrity of files. A checksum is a value which is computed to allow you to check the validity of a file. All files have a unique checksum and if you change even one byte in a file, and then run it through the program again, the result will be different. This is used as a way to verify whether a file has been altered. Camtech Checksums offers two different types of check sums.