Comparison
Blockchain Timestamps vs. Notarization
These are different tools that prove different things. Understanding the distinction matters for claims professionals and litigation counsel who need to choose between them — or use both.
What notarization actually proves
A notary public is a state-appointed official who witnesses the signing of documents and verifies the identity of the signatories. When a notary seals and signs a document, it certifies:
- The signer appeared before the notary in person (or remotely, with remote online notarization).
- The signer's identity was verified (typically via government-issued ID).
- The signer appeared to act voluntarily.
A notary does not certify the contents of the document. They don't verify claims made in it, authenticate photographs embedded in it, or prove when any digital files within it were created. The notary's seal proves the act of signing occurred — not the truth of what was signed or when underlying evidence was created.
What blockchain anchoring proves
A blockchain-anchored timestamp proves one thing with mathematical precision: a specific file, identified by its SHA-256 hash, existed at or before the block timestamp recorded on a public ledger. It does not prove identity, signing, or intent — those are notarization's domain.
What blockchain anchoring does prove is file integrity and timing:
- The exact bytes existed on a specific date. Any modification changes the hash — the record no longer matches.
- The timestamp is on a public ledger no party controls. Neither the submitting party nor ProofLedger can retroactively alter it.
- Verification is adversarial. Opposing counsel, the insurer, or expert witnesses can independently verify without trusting the submitting party or ProofLedger's servers.
Side-by-side
| Property | Notarization | Blockchain Timestamp |
|---|---|---|
| Proves identity of signer | Yes | No |
| Proves file existed at a specific time | Only for documents signed in that session | Yes — any file type, any time before anchoring |
| Binds timestamp to file contents | No — timestamps the signing act, not file bytes | Yes — SHA-256 hash is file-specific |
| Tamper detection if file modified | No | Yes — hash mismatch is detectable |
| Independent verification | Via notary's journal (if retained) | Via any Polygon or Bitcoin block explorer |
| Requires appointment / in-person | Yes (or RON for remote) | No — automated in seconds from any device |
| Cost per document | $5–$25 per signature | Cents per file |
| Scalable to thousands of files | No | Yes — API supports batch workflows |
| Relevant legal standard | State notary law; UCC Article 1 | FRE 901(b)(9); Daubert |
When to use each
Use notarization when:
- You need to authenticate a signature — deed, affidavit, power of attorney
- State law requires notarization for the document type
- Identity verification of the signer is the central evidentiary need
- You're completing a real estate transaction or legal instrument
Use blockchain anchoring when:
- You need to prove a photo, report, or file existed before a specific date
- You're creating pre-loss property documentation at scale
- You need tamper-evidence (any modification breaks the hash)
- You need independent verification without trusting a third party
- You're anchoring hundreds or thousands of files in an automated pipeline
Using both together
For high-stakes litigation, the strongest evidence chain uses both: a notarized affidavit attesting to the circumstances of evidence collection, combined with blockchain-anchored timestamps proving each collected file's integrity and creation timing. The notarization establishes who collected the evidence and how; the blockchain anchoring establishes that the evidence hasn't been altered since collection.