Healthcare Data GlossaryTech
Attestation: Definition and Healthcare Context
Full name: Cryptographic Data Attestation
An attestation is a signed, tamper-evident statement that a specific set of data existed in a specific form at a specific time. In a data-integrity context, each captured source snapshot is hashed and the hash is signed with a cryptographic key, then linked into an append-only chain so the record cannot be altered after the fact without breaking the chain. An attestation does not assert that the underlying facts are correct — it attests, with a signature and timestamp, to exactly what was received from a source and when.
Last updated: 2026-06-17Reviewed by: Dr. Jennifer Montecillo, MD — Gullas College of Medicine, 2019. Non-practicing medical reviewer.
How it’s used
- Each source snapshot is hashed with SHA-256 and the hash is signed with an Ed25519 key, producing a witness signature stored alongside the snapshot.
- Signatures link into a hash chain, so any change to a past record breaks the chain and is detectable on re-derivation.
- An external timestamp anchor records when each signature was made, so the attestation chain cannot be claimed to have been backdated.
Frequently asked questions
- What is a cryptographic attestation?
- A cryptographic attestation is a signed, timestamped statement that specific data existed in a specific form at a specific time, made tamper-evident by hashing the data and signing the hash.
- How is an attestation different from saying data is correct?
- An attestation does not claim the underlying facts are accurate. It attests only to what was received from a source and when, so the captured bytes can be re-derived and the signature checked later.
- What signs Fonteum's attestations?
- Each snapshot hash is signed with an Ed25519 key and linked into an append-only chain, with an external timestamp anchor recording when the signature was made.
Explore in Fonteum
How Fonteum sources, resolves, and publishes data tied to this term.