Protect your work. Prove your document creation without handing it to anyone.

No. We never have access to your file — the hash is calculated directly in your browser. We store the hash, your email address and the description you write, because a certificate cannot be issued or verified without them.

No. You pay by card, and we handle the blockchain transaction for you.

A lifetime certificate containing everything needed to prove a timestamp — your data and the hash stored on the blockchain. Note that a certificate proves the time of the blockchain record, not the file’s creation time, so it proves the file existed before that moment.

Only a hash goes on the blockchain, so your file and its contents stay private. You prove the timestamp by presenting the certificate, which holds all the necessary information — including any email address you chose to add, so use one you are willing to show or leave the field empty.

We send you a link to your blockchain transaction, also included in your certificate, along with instructions for verifying and proving your timestamp independently, without using our service.

Yes. Your certificate contains everything needed to prove your data via the blockchain, entirely independently of us.

If you lose the original file or the certificate, or you modify the file’s content — which changes its hash — you will not be able to prove the timestamp. Keep both safe and untouched.

We use Ethereum, one of the most popular and reliable blockchains available.

Any type of file. One certificate covers up to 10 files, so there is no need to zip them together — it costs one certificate either way. If a file is too large or too sensitive to open in the browser, compute its SHA-256 yourself and paste the fingerprint instead.

Free tools batch many files into a single shared blockchain transaction, so proving yours means reconstructing an inclusion proof, and the free service usually has to still exist for that to be easy. Every certificate here gets its own Ethereum transaction, which costs real money to write. In exchange, verification is one click on a public block explorer and needs nothing from us.

It is accepted as evidence in a growing number of jurisdictions, and it is never conclusive on its own. In March 2025 a French court relied on a blockchain anchoring certificate to establish anteriority in a copyright dispute; Italy recognises blockchain timestamps by statute; US rules on authenticating digital records already accommodate hashes. What a court weighs is the narrow fact the record establishes — that a file existed by a date and has not changed — alongside everything else in the case. See is a blockchain timestamp valid in court for the jurisdiction-by-jurisdiction picture, and proof of existence vs proof of authorship for what it cannot establish.