Date your creation before showing it to the world.
A manuscript, an invention, source code, a mock-up: inscribe its SHA-256 fingerprint on the Bitcoin blockchain and establish, verifiably by anyone, that it was in your hands on a certain date — without revealing a single line of it.
What is a proof of anteriority?
It is an element that establishes that a specific content existed on a given date. It does not say who the author is, nor does it confer any title of ownership: it fixes a fact — “this document, exactly this one, existed on that day” — enforceable over time.
A certain date
The timestamp is inscribed in a Bitcoin block, a public ledger that no party — not even btc3r — can backdate or alter after the fact.
A fixed content
The SHA-256 fingerprint identifies your file down to the bit. The slightest later change — a space, a comma — produces a completely different fingerprint.
A preserved secret
Only the fingerprint is published. Your creation stays confidential: it is impossible to reconstruct the document from its hash.
Those who create before they file
Any situation where an idea circulates — a pitch, a tender, a publisher, an investor — before formal protection is in place.
Before filing a patent
Document the state of your invention on a certain date, without disclosing it: an invention made public before filing loses its novelty. Inscribe the fingerprint of the lab notebook or the technical description, never its content in plain text.
Before sending to publishers
Copyright arises from the creation itself, but you still need to be able to date that creation. Hash your manuscript, screenplay or synopsis before circulating it.
Source code & algorithms
An archive of your repository at a moment in time, a library before release, an algorithm before a partnership: the fingerprint freezes the exact version, file by file or as a full archive.
Visual works & mock-ups
Logos, style guides, mock-ups, photo series: date your source files before presenting them to a client or publishing them in a portfolio.
The mechanisms for proving anteriority
Each mechanism has its place; they can even be combined. Here is what sets them apart.
| Mechanism | Duration | Verifiable by third parties | Confidentiality | Dependency |
|---|---|---|---|---|
| Blockchain inscription (btc3r) | Unlimited, as long as the Bitcoin network exists | Yes, by anyone, via any public block explorer | Total (only the fingerprint is published) | No authority: the proof outlives btc3r |
| Soleau envelope / e-Soleau (INPI, France) | 5 years, renewable once | Via the INPI only | Total | INPI (French public body) |
| Deposit with a notary or judicial officer | Depending on the deed | Via the ministerial officer | Total | The firm and its archives |
| Registered letter to oneself | As long as the envelope stays sealed | Difficult; fragile and contested evidential weight | Total | Physical integrity of the envelope |
The Soleau envelope and the notarial deposit remain proven references; the blockchain inscription complements them with public verifiability, unlimited duration and independence from any authority, for 9.60 € per inscription.
What the law says
Article 1358 of the French Civil Code provides that, except where the law provides otherwise, proof may be brought by any means. A blockchain timestamp is therefore admissible as evidence of a fact; its weight is assessed at the judge’s discretion.
Article 41 of Regulation (EU) No 910/2014 prohibits denying legal effect to an electronic timestamp solely on the grounds that it is not “qualified”. A Bitcoin inscription is not a qualified timestamp within the meaning of eIDAS, but it cannot be set aside for that reason alone.
An inscription dates a content; it proves neither your identity as author, nor the lawfulness of the content, and replaces neither a patent nor an authentic instrument. For an important legal matter, consult a legal professional — and combine mechanisms.
Build your proof in four steps
The fourth only comes into play the day you need it — in a year or in twenty.
Freeze your creation
Gather the final version into a file or an archive. It is this exact version, down to the bit, that will be dated.
Hash locally
On btc3r, the SHA-256 fingerprint is computed in your browser. The file never leaves your computer.
Inscribe the fingerprint
The fingerprint is inscribed in a Bitcoin transaction. Once the block is confirmed, you receive the certificate: TXID, block number, timestamp.
Keep the original
Carefully keep the unchanged file and the certificate. When the day comes, recomputing the fingerprint and comparing it to the one in the block is enough to demonstrate anteriority.
⚠ Key point: the fingerprint alone proves nothing without the original file. Keep several strictly identical copies of the file, on separate media.
Anteriority: what people ask us
Does a blockchain inscription constitute a recognised proof of anteriority?
Under French law, proof of legal facts is free (article 1358 of the Civil Code): a blockchain timestamp can therefore be produced in court as evidence. The European eIDAS Regulation (No 910/2014, article 41) further states that an electronic timestamp cannot be set aside solely because it is not qualified. Its evidential weight remains assessed by the judge: it replaces neither an authentic instrument nor a formal legal deposit.
Do I have to disclose my creation to inscribe it?
No. You only inscribe the SHA-256 fingerprint of your file, computed directly in your browser: the document itself is never transmitted, neither to btc3r nor to the Bitcoin network. The content stays strictly confidential until the day you choose to reveal it.
What should I keep after the inscription?
The original file, strictly unchanged (down to the bit), and the btc3r certificate carrying the transaction TXID. It is the combination of the two that makes the proof: by recomputing the file’s fingerprint and comparing it to the one inscribed on the blockchain, anyone can verify the anteriority.
Does proof of anteriority grant me an intellectual property right?
No. It establishes that a content existed on a given date, which is useful for dating a work (protected by copyright from the moment of its creation) or documenting prior know-how. It replaces neither a patent filing, nor a trademark filing, nor a design filing with the INPI or the EUIPO.
Can I inscribe an invention before filing a patent?
Yes, provided you inscribe only the SHA-256 fingerprint, never the description in plain text: an invention publicly disclosed before filing loses its novelty and becomes unpatentable. The fingerprint reveals nothing of the content while dating it with certainty.
Other ways to use inscription
Document timestamping
Contracts, minutes, reports: freeze the exact state of a professional document.
Learn more →Proof of existence
Show that a file existed on a given date, verifiable by any third party.
Learn more →Understand inscription
OP_RETURN, SHA-256, independent verification: the foundations explained simply.
Learn more →Your idea deserves a certain date.
Inscribe the fingerprint of your creation for 9.60 € : it will be dated, public and verifiable — without revealing anything.