Where COSigna fits

Where COSigna fits — alongside the e-signature service you already use

For agreements that must stay inside your own walls, COSigna's server never receives the document. Everything else can stay with the e-signature service you already use.

How does COSigna fit with the e-signature service I already use?

Alongside it. Your COSignees open a link, see the document, seal it — no account, no app, no upload. You keep one self-contained proof file, with no account to keep alive.

What does risk-free mean?

Risk-free means the people who sign need no account and no card, no data is surrendered, and the test certificate is yours to keep. One ceremony, not a migration — your existing e-signature workflows stay where they are. The proof verifies without us for as long as you keep it.

Is COSigna eIDAS compliant?

Yes — a Simple Electronic Signature, no more claimed. eIDAS Article 25 already protects that: an SES can't be denied legal effect for being electronic. Want more weight? Add a lawyer as a witness-COSignee.

Can a self-hosting company tamper with ceremonies?

No — not because it's watched, because it structurally can't. It holds no keys and never sees a document; the ring itself is tamper-evident, so any alteration fails offline verification, no server needed.

Who controls the timestamp?

Nobody at COSigna. Every ceremony is anchored to the Bitcoin blockchain via OpenTimestamps — a clock no one, including us or a self-hoster, can move.

Stays with your e-signature service

  • Workflows, templates and bulk sends. COSigna does not aim at these today.
  • Identity checks, where your service offers them. COSigna never verifies identity: names are declared.
  • A qualified signature, where one is needed. A party adds their own; COSigna is not a qualified trust service provider.
  • Signing with strangers at a distance. COSigna is built for people who already know each other.

What COSigna adds, inside your own walls

A server that never receives your document, plus open verification anyone can run.

  • The document never reaches COSigna's servers
  • Mutual human (face) attestation
  • Independent timestamp (Bitcoin)
  • Verifiable offline, without COSigna's servers
  • Identity comes from people, not passwords
  • Still verifies if COSigna disappears
COSigna — patent EP3665600B1 · US11531746B2 · FR3070079B1
Report bugCOSigna — a Cryptographic Ring of Mutual Consent · The ring is strong because the loop is closed.The ring is strong because the loop is closed.COSigna