Use case · Contracts

Prove a contract or agreement existed and is unchanged.

Contracts get disputed over versions and dates. Blockchain notarization lets both sides prove which exact document existed when — without either party being able to quietly swap in a different version later.

Why it works here

An anchored fingerprint pins a specific version of an agreement to a specific time. If a dispute later arises about which draft was agreed, or whether a clause was changed, the notarized fingerprint settles the integrity question objectively: the document either matches the anchored hash or it does not.

This complements — it does not replace — a notary’s role in verifying signer identity. Use notaros to fix the document’s existence and integrity, and a commissioned notary where the law requires identity notarization. See the comparison.

Common scenarios

Lock the agreed version

Both parties notarize the final document so the exact agreed bytes are provable.

Timestamp an NDA before sharing

Prove an NDA existed before a disclosure without revealing its terms.

Evidence an amendment’s date

Anchor each amendment to establish the order and timing of changes.

How to notarize for this

Fingerprint your file in your browser, pay $25 in USDC/USDT, and receive a certificate anchored to Base and Bitcoin that anyone can verify independently. Read the full process or the step-by-step guide.

A notaros proof is strong, independent evidence of a document’s existence and integrity at a point in time. It does not establish authorship, ownership, or truth of contents, and its legal weight varies by jurisdiction — consult a qualified professional for a specific matter.