Get independent, third-party proof that your document existed no later than right now. Your file never leaves this computer.
Drop a file here, or click to choose one
Any file. A PDF, a photograph, a spreadsheet, a ZIP of a whole folder.
Your file is not uploaded. It is read inside this page to calculate a fingerprint, and only that fingerprint, 32 bytes, is ever sent anywhere.
What this does. It calculates a fingerprint of your file and asks several independent timestamp authorities to sign a statement that they saw that fingerprint at a particular moment. You get back a single ZIP file holding your document, their signed statements, their certificates, and a plain-English record of everything that was done.
What it cannot do. It cannot show who wrote the document, who held it, or whether anything in it is true. It cannot reach backwards: a file stamped today says nothing about last year. And it fixes only the latest moment your document can have existed, never the earliest.
Use this when the document itself must not leave your control, even to be read by this page. You calculate the fingerprint yourself and paste it here.
sha256sum yourfile.pdf # macOS: shasum -a 256 yourfile.pdf
# Windows: certutil -hashfile yourfile.pdf SHA256
Read this before using it. The archive you get will not contain your document, so on its own it binds to nothing. It becomes meaningful only beside a file that hashes to exactly the value you enter. This tool cannot see what you hashed, and cannot check that you hashed it correctly. Preserving the document is entirely your job.
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Starting
This happens entirely on your computer. Nothing is being uploaded.
Only the fingerprint above is sent. It cannot be turned back into your document.
Send it for me is the ordinary choice. The fingerprint goes through a small relay to each authority. The relay is necessary because timestamp authorities refuse requests made directly by a web browser. It holds no signing key, so it cannot forge or alter a timestamp; the worst it could do is learn the fingerprint, and if it returned a timestamp for a different fingerprint this page would catch it and say so.
I will send it myself keeps everything on your own network. The page gives you the request file and a small script; you run it, then drag the replies back here. Choose this if even the fingerprint must not pass through anyone else's server.
The relay is open source and you can run your own. See the project README.
All of them at once, with the same request.
1. request.tsq has been downloaded. It contains your fingerprint
and nothing else.
2. Download the helper for your system and put it in the same folder as
request.tsq, then run it.
On macOS you may need chmod +x stamp.sh first. Your system may warn
you about running a downloaded script; the whole script is shown below so you can read every line
of it before you do, or simply run the commands yourself.
3. Drag the reply files back here.
Drop the .tsr files here
freetsa.tsr, digicert.tsr, sectigo.tsr, sigstore.tsr
Why there is no single tick. Each check is listed separately because they fail separately, and knowing which one failed is the whole point. A timestamp can carry a perfectly valid signature and still have nothing to do with your document. One green tick covering all of these would hide exactly that case.
Chain to a trusted root is marked NOT RUN on every authority, and this is not a fault. A web browser does not let a page read your computer's list of trusted certificate authorities. The archive contains the exact commands to complete that check with standard software, and they should be run before this timestamp is relied on.