For anything worth proving

Seal it. Prove it, independently.

A tamper-evident, timestamped proof that these exact bytes existed at this moment, checkable by anyone, offline, independently. Only a hash of your work leaves your device, never the work.

1 · The work to seal

Drop any file herea document, an image, a contract, a dataset, or click to choose. It is hashed on your device and never uploaded.

or paste text

Name on the seal (optional, it becomes part of the sealed record):

What a seal is, and is not.

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.

Take it with you. Free.

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, independently.

Request the Sealer, free

Existence, integrity, time. Sealed.

Verify a seal How to buy