For anything worth proving
A tamper-evident, timestamped proof that these exact bytes existed at this moment, checkable by anyone, offline, forever. Only a hash of your work leaves your device, never the work.
1 · The work to seal
or paste text
It is a signed, timestamped record bound to a one-way hash of your exact bytes. Keep the seal with the work: anyone can verify the pair, offline, with no account. Verify one yourself, then change a byte and watch it break.
It is not a judgement of quality or authorship, and it is not a certification. It attests; it does not verdict. Tamper-evident, not tamper-proof. The work itself is never sent or stored; the seal holds only its hash.
The Sealer also runs entirely on your own computer, no internet needed, no account, nothing to sign up for. Download it, double-click, seal files on your desk. Anyone can verify your seals here, free, forever.
Sent by reply, same day. The browser tools above need nothing from you, not even an email address.
Version 1, about 24 MB. What it seals never leaves your machine.
Existence, integrity, time. Sealed.