Frequently Asked Questions

Yes. Proovik issues a non-qualified electronic time stamp within the meaning of Art. 3(16)(i) of Regulation (EU) 910/2014 (eIDAS). Under Art. 41(1), it cannot be denied legal effect or admissibility as evidence in proceedings solely because it is electronic or not qualified. What it lacks is the presumption of accuracy of date and time under Art. 41(2), reserved for qualified time stamps. Proovik does not replace a notary or a qualified trust service provider, and weighing the evidence is always up to the court. Outside the EU, treatment depends on each jurisdiction: consult a lawyer for your case.

Your proof remains valid and checkable. Your document's hash is inscribed in a public transaction on the Kaspa network, replicated across thousands of nodes that do not depend on us. The PDF certificate includes the hash, the transaction id, the timestamp and the Merkle path, and the verification procedure (PVK-PROOF/1) is published on our verification page. Anyone can repeat the check with standard tools, without an account, without our API and without Proovik existing. Keep the PDF next to the original document.

Three practical reasons. Confirmation in seconds: Kaspa uses a proof-of-work BlockDAG that confirms transactions in about a second, versus minutes or hours on other networks. Very low transaction cost, which makes cheap certifications and a free plan possible. And it is a public network: the transaction can be looked up in any Kaspa explorer, so the proof does not depend on Proovik.

Keep it next to the original document: the two together are the proof. You can send it to the other party of a contract, attach it to a file or submit it in proceedings. Whoever receives it can check it on their own: recompute the document's SHA-256, compare it with the one in the certificate and find the transaction on the Kaspa network (the PDF includes the link and a QR code to the explorer). The exact steps are in how to verify a proof.

You can start for free, no card required, and certify your first documents. For larger volumes there are plans with certification bundles; prices are on the pricing page.

That a specific file already existed at a specific date and time. We record your document's digital fingerprint (SHA-256 hash) on the Kaspa network and give you a certificate anyone can check. We do not verify the content, authorship or legality of the document.

No. Proovik proves that a document existed at a specific date and time and has not changed since. It does not attest the identity of the parties nor replace a notary's public faith. For many uses (protecting an idea, fixing the version of a contract, documenting a delivery) it is enough; for others you will also need a notary.

Any: PDF, text documents, images, video, source code, compressed archives. The hash is computed over the file's bytes, so the format does not matter. Note that any change, however small, produces a different hash: certify the final version.

No. The SHA-256 hash is computed in your browser and is the only thing that is sent and recorded. The document cannot be reconstructed from the hash, so nobody, not even Proovik, can read its content.

A cryptographic function that generates a unique 64-character fingerprint for any file. Change a single bit and the hash changes completely, and the original file cannot be reconstructed from it. It is the same algorithm used by Bitcoin and most electronic signature systems.

Recompute the document's SHA-256 with any tool (for example, sha256sum), compare it with the hash in the certificate, follow the included Merkle path and look up the transaction id in a Kaspa explorer. The full specification, with examples, is on the verification page.

It proves that you had that file on that date, not that you created it. In practice, being the first who can prove a work existed is strong circumstantial evidence of authorship, but authorship itself is established by other means. If you need advice for your case, consult a lawyer.

A qualified time stamp is issued by a provider on the EU trusted lists and enjoys the presumption of accuracy of date and time (eIDAS, Art. 41(2)). Proovik's time stamp is not qualified: it lacks that presumption, but it is admissible as evidence (Art. 41(1)) and, unlike a qualified time stamp, anyone can independently check it on a public network without trusting the issuer.

The record relies on two things we do not control: the SHA-256 algorithm, an industry-wide standard, and the Kaspa network, maintained by thousands of independent nodes and miners. Neither Proovik nor anyone else can alter a confirmed transaction. And your document never leaves your device.

The document's hash, the date, the transaction id and, if you have an account, your email address. Only the hash is inscribed on the Kaspa network: neither your name nor the file name. Details are in our privacy policy.