checksumbased

Checksums-based, or checksum-based, refers to methods and systems that rely on a checksum value to verify data integrity. A checksum is a small datum computed from a data set, such as a file, packet, or block of storage. After data is created or transmitted, a checksum is calculated and stored or transmitted with the data. Upon reception or retrieval, a new checksum is computed and compared to the original; a match indicates that the data has likely remained unchanged, while a mismatch signals corruption or alteration.

Checksums-based approaches are used primarily to detect accidental errors introduced by transmission or storage faults. They can operate at various granularities, from single blocks to entire files or streams. Algorithms fall into two broad categories. Simple checksums such as CRCs (cyclic redundancy checks) and Adler-32 are fast and good at catching common errors but are not designed to resist deliberate tampering. Cryptographic hash functions such as MD5, SHA-1, and SHA-256 can be used to create stronger fingerprints, but some of these algorithms have known weaknesses and may be unsuitable for security-critical integrity guarantees without additional protections.

Common applications include software distribution, where publishers publish checksums to enable users to verify downloads; backup and archival verification; file synchronization; and content-addressable storage, where data are identified by their checksums or hashes.

Limitations include the possibility of collisions, the fact that a checksum alone does not prove authenticity, and the need for secure channels or digital signatures when tamper resistance is required. See also hash functions, data integrity, and digital signatures.