Checksums

Part of speech: noun

Definitions

1. Numerical values calculated to verify the accuracy and integrity of data in files or messages
2. Numbers derived from data used to confirm that information has not been altered or corrupted
3. Digital codes generated for checking whether data has been transmitted or stored without errors

Etymology: "Checksums" is the plural of "checksum," a compound of "check" and "sum." The sense is literal: a checksum is a sum taken for the purpose of checking. Its parts keep their ordinary meanings. "Check" comes from the idea of verifying or testing something against a standard, and "sum" is the total produced by adding numbers together. Put together, the term names a total computed from a body of data, which is then compared against a stored or expected total to reveal whether the data has changed. The idea behind the compound is that the sum acts as a fingerprint. Recompute it later, and any mismatch signals that something was altered or corrupted along the way. The word therefore describes both the arithmetic and the purpose behind it, a pattern common in technical coinages where ordinary words are combined to name a new procedure.

Synonyms: hash, digital signature