File Checksums

A checksum (also known as hash sum) is a fixed size value which is computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. It basically allows us to check the validity of something. Usually, checksums are used in data transmission contexts to detect if the data has been transmitted successfully. The integrity of the data can be checked at any time later on, by recomputing the checksum and comparing it with the stored one. If the checksums do not match, the data was certainly altered, either intentionally or unintentionally.