firmiu
Firmiu

Verify a document

Check that a document signed with Firmiu is authentic and was not modified. No account needed.

You'll find it on the certificate page, at the end of the signed PDF.

PDF fileoptional

If you upload it, we check that it's exactly the file that was signed. The PDF is never sent to Firmiu: the fingerprint is computed in your browser.

How it works

  1. 1

    Every document carries a reference number

    When signing completes, Firmiu appends a certificate page to the PDF with the reference number, each signer's details and the document's SHA-256 fingerprint.

  2. 2

    The reference is checked against the record

    We look that reference up in our records and show who signed and when. Verification data only: nothing about the account that sent the document.

  3. 3

    The fingerprint catches any change

    If you upload the PDF, your browser computes its fingerprint and compares it with the one we stored. A single different character makes them disagree.