Proof that does not depend on us
When a document is completed, its fingerprint goes into a Bitcoin block. Years later anyone can show the file existed at that moment, even if sign.yt is gone.
What gets anchored
sign.yt anchors the SHA-256 hashes of the signed PDF, of the audit trail and of the head of the audit chain through OpenTimestamps. Only hashes leave the platform, never the document or any personal data.
The proof is usually confirmed in a Bitcoin block within a few hours.
Check it yourself
The evidence ZIP contains the .ots proof and the list of anchored hashes. Verify them with the open-source ots client, against any Bitcoin node or block explorer, without an account and without contacting us.
The public verification page also shows the anchor status and the block height, with a link to the block.
Why a blockchain
A database row can be edited by whoever runs the database. A Bitcoin block cannot be changed by anyone. That makes the anchor a strong, independent answer to the question "did this file exist on that day, in exactly this form?".
Frequently asked questions
Does sign.yt put my document on the blockchain?
No. Only hashes are anchored. A hash reveals nothing about the content, but any change to the file gives a different hash.
Do I pay for Bitcoin transactions?
No. Public OpenTimestamps calendars combine many hashes into one transaction, so there is no fee per document.
How long until the proof is final?
Usually a few hours. Until then the anchor shows as pending; the proof upgrades automatically.
More features
- Public verification
Each signed document carries a QR code and short link to a public check page. Masked names, signing dates, seal status and a file comparison.
- Profil Zaufany and qualified signatures
Let Polish signers use Profil Zaufany, e-dowód or mObywatel via Węzeł Podpisu, or sign with a qualified electronic signature from a trust service provider.
- Audit trail
Every action is logged in an append-only, hash-chained audit log. Signatures are chained per document and a certificate of completion is added to each PDF.