Blockchain timestamp & proof of existence for any file
Someone stole your work? Prove you created it first.
Once they publish your work as theirs, you are the one who has to show it was yours first. As of 2026, ProofSnap timestamps any file on the Bitcoin blockchain and can add a qualified eIDAS timestamp recognized across the EU, so you can show it existed in this exact form on a given date. $4.99 one-time, hash only.
Also available for Microsoft Edge
7 days free, then $4.99 one-time or $8.99/mo · No file upload, hash computed locally · Works with any file type
File certification is included in every ProofSnap plan. ProofSnap also captures full web pages as forensic evidence: screenshots, HTML, metadata, blockchain timestamps, and chain of custody. Learn more about web evidence →
Available on Chrome Web Store · No access to your personal data · Installs in 30 seconds
By Radim Motycka, Founder and Lead Engineer at ProofSnap, who built the hashing, signing and timestamping pipeline described on this page · · Any package is independently checkable in the Trust Verifier
How file certification works
Three steps. Your file never leaves your device.
Drag & drop your file
Open ProofSnap and drag any file into the extension. Documents, images, code, designs, audio, video, any file type works.
SHA-256 hash computed locally
ProofSnap computes a SHA-256 hash of your file entirely in your browser. Your file never leaves your device; only the 64-character hash is used.
Hash anchored to Bitcoin blockchain
The hash is anchored to the Bitcoin blockchain via OpenTimestamps. A provenance certificate PDF is generated as your proof of existence.
Has a court actually accepted a blockchain timestamp?
Yes, and the clearest example is recent. On 20 March 2025 the Tribunal judiciaire de Marseille, First Civil Chamber, decided case RG 23/00046 between the fashion house AZ Factory and the wholesaler Valeria Moda. AZ Factory could not rely on its bailiff seizure report, which the court annulled for a procedural defect. What carried the claim instead was a set of SHA-256 fingerprints anchored on the Bitcoin blockchain in May and September 2021, the same technique this page describes.
“The Court accorded full probative weight to the ‘Blockchain timestamp reports’ dated 5 May 2021 and 15 September 2021, as corroborated by a bailiff’s verification report dated 19 October 2022. The Court adjudicated that these elements, in conjunction with evidence of public disclosure, constituted a consistent body of evidence (faisceau d’indices) establishing the claimant as the proprietor of the copyright from the dates recorded on the distributed ledger.”
The court awarded EUR 11 900 in damages, ordered the infringing goods destroyed and required the judgment to be published in three trade journals. The holding also tells you how to use a timestamp well. It worked as part of a faisceau d’indices, a consistent body of evidence, alongside proof that the designs had been publicly disclosed. That is the practical lesson for anyone reading this page.
Three things to keep alongside the timestamp
- The working files, not only the export. Layered sources, project files and version history show the work being made, which a single flattened image cannot.
- A record of public disclosure. The Marseille court weighed the timestamps together with evidence that the designs had been shown publicly. A dated portfolio page or a launch post does that job.
- The certificate and the .ots file, kept together. Once the proof is complete, anyone can re-hash the original file and check it against a Bitcoin node without contacting ProofSnap, which is what makes it survive any vendor, ours included.
How long before the timestamp is confirmed?
The certificate is issued in seconds, but the Bitcoin anchor is not instant. OpenTimestamps calendar servers aggregate many hashes and pack them into a Bitcoin transaction, so the proof has to wait for a block. That is why the provenance certificate records the blockchain row as SUBMITTED, with the completed proof in manifest.json.ots. What that proof establishes is that your file existed before the block carrying it, an upper bound on the date, which is exactly what a priority dispute turns on. A qualified eIDAS timestamp behaves differently, because a qualified trust service provider signs it on the spot.
6 reasons creators, developers and businesses timestamp their files
Any file where you need to prove “this existed on this date, in this exact form.”
Copyright & IP Protection
Prove you created it first. Timestamp your manuscript, song, design, photograph, or source code before publishing.
What is digital provenance? →Contracts & NDAs
Timestamp the version everyone signed. If someone later produces different terms, the certified copy shows which wording existed on which date.
Code Provenance
Timestamp your git commits, releases, or security audits. Prove your code existed in a specific state on a specific date.
Academic Research
Establish priority of discovery. Timestamp your findings, datasets, or pre-prints before peer review.
Design & Creative Work
Prove your design, logo, or artwork existed in this exact form before a competitor published theirs. The timestamp fixes the date; your working files carry the rest. If someone has already copied your photo, see how to prove photo ownership after image theft.
Deepfake Countermeasure
Certify your media the day you shoot or render it. Any later edit produces a different hash, so the certified copy is the one that can be shown to be unchanged.
Deepfake evidence & provenance certificates →Without proof of when you created it, you have nothing.
These disputes happen every day. The creator who can prove the earliest date wins.
Freelancer sends logo concepts to client. Client ghosts, then uses the design without paying. Without a timestamp proving the designer created it first, it's their word against the client's.
Common in: graphic design, branding, UX/UI
Business partner claims the NDA was different from what was signed. Without a timestamped copy of the exact version they signed, courts treat it as he-said-she-said.
Common in: partnerships, vendor agreements, employment
Developer builds a tool, co-founder claims ownership. Git history can be rewritten. A blockchain timestamp of the codebase fixes what existed, and on what date, in a record neither side can rewrite.
Common in: startups, open source, freelance dev
The cost of not timestamping: legal fees, lost IP, disputed contracts. The cost of timestamping: $4.99. Once.
What you get per certified file
Every file certification generates a complete evidence package: blockchain timestamp, digital signature, provenance certificate, and chain of custody.
provenance_certificate.pdf
Provenance proof (4 checks)
verification/
Offline verify scripts and guide
manifest.json.ots
Bitcoin blockchain timestamp
manifest.sig
Digital signature (RSA-4096)
manifest.json
SHA-256 hashes of all files
publickey.pem
Verification public key
forensic_log.json
Complete forensic log
chain_of_custody.json
Verifiable chain of custody
Your original file + all certification files download as a ZIP. A qualified eIDAS timestamp is available on the Enterprise plan and through the eIDAS SnapPack.
What the provenance certificate looks like
PROVENANCE CERTIFICATE
provenance_certificate.pdf
- File
- logo_final_v3.ai
- Certified
- 2026-09-13 09:41:07 UTC
- SHA-256
- 9f2c4e1b7a83d05f6c19ab42e7d8035b1cf6a97e204d8b3e5a71c9d0f4e26b8a
Integrity checks
- SHA-256 Hash PASS
- RSA-4096 Signature PASS
- Blockchain (Bitcoin) SUBMITTED
- EU Qualified (eIDAS) SUBMITTED (qualified)
The original file never leaves your device. Only its SHA-256 hash is sent to timestamp servers.
Hashed and sealed
SHA-256 · Bitcoin timestamp
Illustrative example, shown with a qualified eIDAS timestamp enabled. Both timestamp rows read SUBMITTED because the certificate is written before the stamps come back: the confirmed answers land in manifest.json.ots and manifest.json.tsr.
Your file never leaves your device
ProofSnap computes the SHA-256 hash locally in your browser using the Web Crypto API. Only the hash, a 64-character string, is sent for timestamping. Not your file. Not a preview. Not metadata. Just the hash. Zero privacy risk.
How ProofSnap compares
OriginStamp retired its self-serve Timestamp Dashboard in 2025 and now sells an enterprise archiving platform. ScoreDetect sells a monthly subscription. ProofSnap starts at $4.99 one-time and bundles the forensic evidence package the other two do not publish. Competitor rows below are what each vendor states on its own site, checked September 2026; "not stated" means exactly that.
| Feature | ProofSnap | ScoreDetect | OriginStamp |
|---|---|---|---|
| Price | $4.99 one-time | From $11.31/mo | Dashboard retired |
| Files included | 5-50/mo (plan) | Not stated | Not offered |
| Blockchain | Bitcoin (OTS) | Bitcoin | Bitcoin |
| eIDAS qualified | Enterprise and eIDAS SnapPack | Not stated | Not stated |
| Provenance cert | Yes (4 checks) | Not stated | Not stated |
| Web capture too | Yes | Not stated | Not stated |
| Local processing | Yes, in the browser | Hashed on device, per ScoreDetect | Not stated |
What a timestamp is worth in evidence
A Bitcoin timestamp is a technical fact anyone can re-check: the hash of your file was published at a point in time, and it has not changed since. What a court makes of that is decided case by case, and the Marseille judgment above shows one court giving it full probative weight. Separately, one rule states an effect in writing: under Article 41(2) of Regulation (EU) No 910/2014, a qualified electronic timestamp carries a presumption of the accuracy of the date and time it shows and of the integrity of the data bound to it. That presumption applies in every EU member state, and it attaches to the qualified timestamp, not to the Bitcoin anchor. ProofSnap issues qualified timestamps on the Enterprise plan and through the eIDAS SnapPack, with Disig a.s., a Qualified Trust Service Provider on the EU Trusted List.
Or we do it for you
You send the files. We send back the sealed package.
Some files are better certified by someone other than the person whose ownership is in dispute. If the matter is already contested, or you simply do not want to install anything, send us the files and we run the same forensic pipeline on our side. You get the signed ZIP, the provenance certificate and a qualified eIDAS timestamp, and the certification is performed by a third party rather than by you.
File Certification, done for you
1 evidence item, certified within 24 hours
$59.99
- Documents, designs, source archives, photos, audio, video
- One evidence item can be several related files
- Qualified eIDAS timestamp and Bitcoin anchor, both included
- Signed ZIP and provenance certificate PDF
Add a signed technical report at checkout, $24.99. What we received and how it was sealed, signed by the examiner. Any jurisdiction, 29 languages.
Same forensic engine as the extension, run by us. Qualified eIDAS timestamps issued by Disig a.s., a Qualified Trust Service Provider on the EU Trusted List under Regulation (EU) No 910/2014.
Not sure which one fits? Tell us what you have and we will scope it →
Prefer to do it yourself? The self-service pricing is below.
Just need to certify a few files? This is all you need.
SnapPack: $4.99, 3 file certifications
One-time payment, no subscription. Includes 3 file certifications and 10 web captures. The web capture credits never expire; the file certification credits are valid for 12 months.
Prove it's mine, from $4.99Need ongoing certifications? Monthly plans
7-day free trial on all plans. Cancel anytime.
Essential
100 web captures/mo
- File certification: 5/mo
- Provenance certificate
- Capture process video
- Blockchain timestamp
- EU qualified timestamp (eIDAS)
Professional
200 web captures/mo
- File certification: 15/mo
- Everything in Essential
- Blockchain (OpenTimestamps)
- EU qualified timestamp (eIDAS)
Enterprise
Unlimited web captures
- File certification: 50/mo
- Everything in Professional
- EU qualified timestamp (eIDAS)
- Email support · response within 1 business day
Annual plans save around 20%. See all pricing options
7 days free, then $4.99 one-time or $8.99/mo
Not sure? Download sample evidence package (ZIP)