Hashanchored

Hashanchored is a data integrity technique in which the cryptographic hash of a data item is anchored to a trusted reference, enabling verification that the item has not been altered and that it originated from or is authorized by the anchor.

In practice, a hash is computed over the content, and the digest is published to a tamper-evident anchor such as a time-stamped registry, a certificate transparency log, or a blockchain transaction. The anchor provides evidence that the hash existed at a specific time and under a given authority.

Verification involves re-computing the hash, retrieving the anchor, and confirming the link between them and any provenance chain, including signatures or certificates that authenticate the anchor.

Applications include software supply chain security, digital document verification, archival integrity for digital libraries, and controlled data sharing in research and government records.

Implementation considerations include choosing a strong hash function (for example SHA-256 or SHA-3-256), selecting an appropriate anchor mechanism, and ensuring timing guarantees. Privacy and performance concerns can be addressed by using canonical data forms or salted hashing where appropriate.

Limitations and risks involve reliance on the security and availability of the anchor, the potential need for anchor revocation or migration, and the necessity of robust key management and incident response in case the anchor is compromised.

See also: cryptographic hash, digital signature, certificate transparency, blockchain, tamper-evident registry.