FAQ

Common FilePruf questions, ordered by what people usually ask first.

1. What is FilePruf?

FilePruf creates a cryptographic proof that a specific file fingerprint existed at a point in time. It calculates a SHA-256 hash in your browser, then anchors a proof message to the blockchain destination you choose.

2. Does FilePruf upload my file?

No. Your original file stays with you. The normal browser workflow hashes the file on your device and sends only the SHA-256 fingerprint plus proof metadata. Even the FilePruf evidence ZIP is programmatically created client side, not on the server.

3. What does FilePruf prove?

FilePruf proves that the exact file fingerprint existed no later than the blockchain timestamp. In practical terms, it helps prove that something did not happen after that point in time, because a later forgery or edited file would create a different fingerprint.

4. What is a SHA-256 fingerprint?

A SHA-256 fingerprint is a 64-character cryptographic hash calculated from the exact bytes of a file. Example: 9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08. If even one byte changes, the fingerprint changes. The chance of two different real-world files producing the same SHA-256 hash is about 1 in 10 to the power of 77.

5. Can someone see my file from the hash?

A SHA-256 hash is not the file contents. For normal private files, someone cannot reconstruct the file from the hash alone. Avoid hashing public or easily guessed tiny content if secrecy of the content itself is important.

6. What do I get after creating a proof?

You get a saved proof record with the file hash, destination, timestamp, transaction identifier, and verification details. If enabled, you can also create an evidence ZIP for offline keeping.

7. Why do I need to keep the original file?

The proof verifies the original file by hashing it again and comparing that new hash with the saved FilePruf fingerprint. Without the original file, you can still show that a fingerprint was recorded, but you cannot prove which file produced it.

8. Why keep the evidence ZIP?

The evidence ZIP can include proof metadata, a certificate-style summary, a verifier tool, and instructions. It is designed to be kept with the original file for future verification. Some apps, export tools, cloud sync services, and file-transfer workflows can sometimes alter file bytes without making the change obvious, so keeping the exact original file inside a ZIP can help preserve the version that was actually proved.

9. Can moving a file around change the proof?

Sometimes. Simply copying a file should usually preserve the bytes, but some software can re-save, optimise, compress, strip metadata, convert formats, or otherwise alter the file without making the change obvious. That is why FilePruf encourages keeping the exact proved file in an evidence ZIP.

10. How do I verify a proof later?

Use the saved proof or evidence ZIP, then compare the original file's SHA-256 hash with the FilePruf proof hash. For blockchain proofs, also check that the transaction contains the FilePruf proof message.

11. What does "Blockchain it" mean?

It means FilePruf records the file fingerprint as a proof by broadcasting a small proof message to a supported blockchain destination. The blockchain record provides an independent timestamped record that becomes virtually impossible to alter after confirmation.

12. Which blockchain should I choose?

Choose the destination that matches your verification need, cost tolerance, and expected audience. Larger networks such as Bitcoin and Ethereum generally have more computing power, economic value, validators, and public scrutiny backing them, which can make them stronger for high-value proof. They are also usually more expensive. Lower-cost chains can be useful when cost matters more than maximum security. Test destinations are for testing.

13. What information may become public?

If a proof is anchored to a public blockchain, the proof message, transaction identifier, and timestamp-like blockchain data may be public. FilePruf does not intentionally publish your original file.

14. Is this legal proof?

FilePruf provides technical evidence, not legal advice. Whether it is accepted by a court, platform, regulator, or other third party depends on the situation and their rules. Some countries do admit blockchain evidence because it can be reliable when properly authenticated. For example, courts in some countries have recognised blockchain evidence under certain conditions since 2018, including in copyright, IP, and internet-related disputes. In France, a 2025 decision accepted a public blockchain timestamp as admissible evidence relating to copyright ownership of fashion designs. In the United States, courts generally treat blockchain records like other electronic evidence: they may be admitted if properly authenticated and shown to be reliable, and several states have passed laws recognising blockchain records or smart contracts.

15. Can FilePruf prove I own a file?

FilePruf proves that a matching file fingerprint existed no later than a recorded time. It does not automatically prove authorship, ownership, copyright, licensing rights, or legal priority by itself. It can, however, support a wider evidence package showing that you had a document, design, photo, source file, or contract at a particular time.

16. How does FilePruf help if someone forges a document later?

If someone alters the original after your proof time, the altered file should produce a different SHA-256 hash. Your FilePruf proof can show that the earlier version already existed before the later change, which is useful when someone tries to backdate or modify a document after the fact.

17. Can I use FilePruf for contracts or invoices?

Yes, provided you have the right to process the file. A proof can help show that the exact contract, invoice, purchase order, or signed PDF existed before or around the proof time. In a contract dispute, that can help authenticate the version that existed on the date it was signed.

18. Can FilePruf help with IP, trademarks, patents, or ideas?

It can help create timestamp evidence that you had a design, draft, source file, business plan, invention note, brand concept, or creative work by a certain time. It is not a substitute for formal patent, trademark, or copyright advice, but it can be useful evidence when you need to show you did something before another person, especially when a formal filing is too expensive or not yet available.

19. What are common FilePruf use cases?

Common examples include landlords authenticating a ZIP folder of move-in photos, tenants recording property condition before handing keys back, parking inspectors proving when photo evidence existed, creators proving early artwork or writing drafts, designers proving fashion or product designs, businesses timestamping contracts and invoices, engineers recording source code or build artifacts, inventors showing they had an idea before someone else, founders preserving pitch decks, researchers timestamping lab notes, photographers proving image files existed, agencies protecting campaign assets, and small creators creating evidence when a patent, trademark filing, or formal IP process is too expensive or not yet available.

20. Can landlords or tenants use FilePruf for property condition photos?

Yes. A landlord can authenticate a ZIP folder of move-in photos to record the original state of an apartment. A tenant can also timestamp move-out photos, repair evidence, correspondence, or inspection files. FilePruf proves the file set existed by the proof time; it does not replace good inspection notes or tenancy-law advice.

21. Can parking inspectors or field teams use FilePruf?

Yes. A parking inspector, insurance assessor, delivery driver, site supervisor, or field worker can timestamp photo evidence so there is a stronger record of when the photo file existed. The proof does not independently prove location or truth of the scene, but it can support the surrounding evidence trail.

22. What kinds of files can I use?

You can use documents, photos, invoices, designs, code, contracts, audio, video, ZIP folders, or any other file your browser can read. FilePruf hashes bytes, so the file type matters less than keeping the original file unchanged.

23. What happens if I edit the file later?

The edited file will have a different SHA-256 fingerprint. The original proof will still match the original version, not the edited version. Create a new proof for each meaningful version.

24. Can I prove a photo was taken at a certain place?

FilePruf can prove the photo file fingerprint existed at a time. It does not independently prove where the photo was taken or whether the scene is authentic. Location evidence, EXIF metadata, witness evidence, and chain-of-custody notes may still matter.

25. What if FilePruf is unavailable later?

If you have the original file, proof details, and any blockchain transaction information, you can still independently verify the hash and public transaction. Keeping an evidence ZIP helps.

26. Does FilePruf store my payment details?

No. Card and wallet checkout details are handled by payment providers such as Square or PayPal. FilePruf receives payment status needed to complete the proof workflow.

27. Why do I have to pay?

Payments can cover blockchain network fees, payment processing, hosting, maintenance, and support for proof infrastructure.

28. Do I need an account?

Some proof workflows may work without a full account, but signing in helps keep proof records connected to you and makes it easier to find saved proofs later.

29. Can I delete a proof?

FilePruf may be able to remove or hide service records depending on account and admin settings. Public blockchain transactions cannot normally be deleted once confirmed.

30. What should I do before sharing a proof?

Keep the original file, keep the proof or evidence ZIP, and make sure the recipient understands that verification depends on matching the original file's hash to the saved fingerprint.

31. Who do I contact with questions?

Send questions to info@filepruf.com.