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A notary or a hash: which one do you need?

2026-11-05 · OpenStela

They prove different things, so the honest answer is "it depends on what you're trying to show." A notary vouches for a person: this human, whose ID was checked, signed or swore to this document in front of a public officer on this date. A hash vouches for a file: these exact bytes are the ones this fingerprint was computed from, and once the fingerprint is timestamped, they existed by that date. A notary can't tell you which file you meant. A hash can't tell you who you are.

For most AI creators dating a song, a video or a character sheet, a hash timestamp is the everyday tool: cheap, instant, and it covers every draft. A notary is worth the trip when someone on the other side needs a checked identity attached to a statement, or when you're making a contract that should carry legal weight of its own. If you want both, you can tie them together: put the file's hash inside the statement the notary handles. The rest of this post explains each piece, using Taiwan's Notary Act and California's official notary handbook as the two worked examples.

What a notary actually checks

The clearest single sentence comes from California. Every acknowledgment and jurat certificate taken in the state carries a printed box, reproduced in the Secretary of State's 2026 Notary Public Handbook (January 2026):

A notary public or other officer completing this certificate verifies only the identity of the individual who signed the document to which this certificate is attached, and not the truthfulness, accuracy, or validity of that document.

The handbook lists what the notary does vouch for. In an acknowledgment: that the signer personally appeared on the date and in the county shown, who the signer is, and that they acknowledged signing. In a jurat: the same, plus that they signed in the notary's presence and the notary gave them an oath or affirmation. Identity rests on "satisfactory evidence," usually an ID document. The notary also keeps a sequential journal recording the date, time and type of each act, the kind of document, and the signer's signature. Rules differ by state, so treat California as one example, not the US rule.

Taiwan's Notary Act (last amended 2019-04-03) splits the work into two acts, set out in Article 2:

• Notarization (公證): the notary drafts a notarial deed about a legal act or a fact concerning private rights. Article 73 requires the requester to show ID. Article 71 has the notary look into the requester's real intent and the facts, and explain the legal effect. Article 80 says the deed records what the notary heard, what they saw, and how they experienced it.
• Authentication (認證) of a private document: under Article 101, the person signs the document in front of the notary, or confirms the signature is theirs, and the notary records that.

Three more details matter. Article 18 keeps the deed's original, and copies of authenticated documents, at the notary's office. Article 14 binds the notary to confidentiality. And a sworn version of authentication exists, but Article 102 limits it: the notary may have you appear and swear to a private statement of facts only when the document is going abroad, or when a law lets that kind of statement serve as proof to a court or agency.

In both places, a notary is strong evidence of who did what when, in front of them. Neither judges whether your drawing is original or whether the file you mention is the file you'll show later.

What a hash actually proves

A hash, such as SHA-256, turns any file into a fixed 64-character fingerprint. Change one byte and the fingerprint is completely different. Two practical consequences:

1. It identifies content exactly. If the fingerprint you recorded matches the file you produce later, the file hasn't changed. Not "looks the same": the same bytes.
2. It carries no identity and no date by itself. Anyone can compute the hash of any file they hold. The fingerprint becomes evidence of a date only when it's written somewhere that can't be backdated: a public blockchain through OpenTimestamps, a registry that anchors to a chain, or a notarial document.

So a timestamped hash answers one narrow question very well: did this exact file exist no later than this moment? It says nothing about who made it, who owns it, or whether it copies someone else. Is OpenTimestamps enough, or do I need a registry? covers the do-it-yourself version step by step.

Side by side

Fees and rules checked 2026-11-05 against Taiwan's Notary Act on law.moj.gov.tw and California's 2026 handbook. Taiwan adds half the fee for work outside office hours (Art. 122).

When a notary is the right tool

A notary earns the visit in situations where the identity check is the point:

• A contract with a buyer or client who expects one. If you're selling the rights to a character or licensing a song, a notarized or authenticated signature makes it hard for either side to later say "I never signed that."
• A Taiwanese deed that should be directly enforceable. Under Article 13, a notarial deed for paying a fixed sum of money (and a few other kinds of performance) can state that it is subject to direct compulsory enforcement, and then enforcement can proceed on the strength of the deed itself. A licence fee written into such a deed is a different kind of document from a dated file. No timestamp does that.
• A document someone else must accept. If a foreign agency or a counterparty asks for a notarized declaration, a hash won't satisfy it.
• A single, important statement. "I made these 12 tracks between March and June, using these tools, and here is what I contributed." One sworn or signed page, once.

When a hash is the right tool

• Every draft and every release. You'll make dozens of versions. A hash costs nothing per file, so the trail of how the work developed gets dated as it happens, not reconstructed later.
• Proving the file didn't change. If a dispute turns on which version came first, or whether a file was edited after the fact, the fingerprint is what settles it. A notary's journal, at least in California's version, records the type of document, not its bytes.
• Right now, at 2 a.m. Creative work often gets finished outside office hours, and a hash doesn't need an appointment.

The limit to keep in mind: a hash alone ties the file to a date, not to you. You supply the link between yourself and the file some other way: your account, your drafts, your project files, your public posts, or a notary.

Using both: put the hash in the notarized statement

This is the combination that covers both gaps, and it costs one appointment.

1. Freeze the final file. Export it and don't re-save it.
2. Compute its SHA-256. On macOS or Linux: shasum -a 256 yourfile.wav. On Windows PowerShell: Get-FileHash yourfile.wav. Copy the 64-character result.
3. Timestamp the hash. Use OpenTimestamps, or register the file on OpenStela (see below). Either way the fingerprint gets an independent date.
4. Write a one-page statement. Name the file, paste its SHA-256, give the date you made it, the tools you used and what you did yourself. Sign it in front of the notary (Taiwan: authentication under Article 101; California: acknowledgment or jurat).
5. Keep everything together. The original file, the hash, the timestamp proof, and the notarized page, in two places.

Now the notarized page ties a checked identity to a statement on a date, and the hash ties that statement to an exact file. The notary still didn't check that your contribution statement is true, only that you signed it. In a jurat, though, you swore to it, which raises the stakes for writing something false.

Where OpenStela fits

OpenStela is on the hash side of this table. It doesn't check government ID. You sign in with Google, GitHub or a sign-in link sent to your email, and that's the whole identity check. Nothing here is a notarial act.

When you register a work, we build an authorship record: the file's SHA-256 fingerprint, the name you publish under, your stated creation date, the tools you used, a rights declaration and, if AI was involved, your own description of what you contributed (required for AI works). The record's hash goes into that night's Merkle batch, and the batch root is written to Arbitrum One. Once written, the record is frozen. Only the title, a note and the public setting can change. Anyone can paste a fingerprint into the verify page, and the downloadable Proof Pack lets the check be redone offline. Once a song is registered, how do you prove it existed that day walks through that.

That adds context frozen with the date. It adds nothing a notary does: we don't check who you are beyond your login, and we don't check that your contribution text is true. Registering works is free within 300 MB of uploads per account and a daily cap; characters are free up to 50 per account; the only fee is 5% (minimum $15) to the seller when a sale reaches the transfer step. See pricing. For the line between evidence and ownership, read What a character ID proves, and what it doesn't, and for three more methods, Five ways to prove a file existed on a date.

This is general information, not legal advice. Notary rules differ by country and by US state, so ask a local notary what their certificate covers.