checksum

A checksum is a small piece of data, typically a number, generated from a larger set of data like a file or message. Its purpose is to verify data integrity by detecting errors that might have occurred during transmission or storage. When data is sent or saved, a checksum is calculated and sent or stored alongside it. When received or retrieved, the checksum is recalculated and compared to the original. If they match, the data is likely unchanged and intact; if not, errors are detected, prompting a need for retransmission or correction.