Checksum Verification
Computing a mathematical fingerprint of a file and comparing it later to confirm the data has not changed.
Measured in
hash
In depth
A checksum turns file integrity from an assumption into a measurement. Recording hashes at ingest allows every subsequent copy to be verified, so a failed transfer or a corrupted archive is detected immediately rather than years later. It is the only way to know that a backup actually holds what it claims to.
Examples in practice
Verifying an ingest catches one file that copied incorrectly, before the memory card is formatted.