hesela.devChecksum
A checksum is a value computed from specified data and later compared with a reference value to detect changes.
A checksum names a checking role, not a security level: storage systems can use a CRC or a cryptographic digest in that role. Btrfs supports both categories. State the covered bytes, algorithm and location of the reference value; disagreement alone does not identify which copy is correct. [1] [2]
Relations
- related
- cryptographic-hash, hash-collision, data-scrubbing, end-to-end-data-protection
Limitations
- CRC error-detection properties depend on the polynomial, message length and error model; CRC is not an authentication mechanism. [3]
- A valid checksum alone does not establish the requested address, committed generation or successful repair. [4]
Citations
- NIST CSRC glossary: checksum (definitions with source attribution)
- Btrfs documentation: Checksumming, algorithm choices and verification boundary
- RFC 3385: iSCSI CRC/Checksum Considerations, sections 1-2 and 10 (historical error-model analysis)
- Hesela: Why a valid checksum can still return the wrong data