Evidence that survives the quantum era
Today's signatures rely on maths that a large quantum computer could break. sign.yt adds a hybrid post-quantum seal, so your evidence keeps its value for decades.
Two algorithms, both must hold
The seal signs a manifest that binds the hash of the final PDF, the head of the audit chain and the signer evidence. It is signed twice: with ML-DSA-65 (FIPS 204, post-quantum) and with Ed25519. The seal is valid only if both signatures verify, so it holds as long as either algorithm stays unbroken.
It is supplementary evidence next to the PAdES signature, not a replacement for a qualified signature.
Verifiable offline
The seal file is part of the evidence ZIP. Upload it with the PDF to the public verifier, or check it offline against the published public keys.
An offline root key certifies or revokes the working keys. Its private half never touches a server. A leaked working key can be revoked, and seals from revoked or uncertified keys fail verification.
Frequently asked questions
Why do I need this today?
Contracts are kept for years. An attacker can store signed files now and try to forge them once quantum computers are strong enough. The seal closes that gap.
Does it replace the PAdES signature?
No. PAdES stays the standard signature that PDF readers understand. The post-quantum seal is an extra, independent layer of evidence.
What is ML-DSA?
A digital signature algorithm standardised by NIST in FIPS 204, designed to resist attacks by quantum computers.
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.