Verify PDF signatures

How it works

1. 1

   Drop a signed PDF — the file is read entirely on your device, never uploaded.

2. 2

   Press Verify — a worker walks the raw bytes: every /FT /Sig field, the CMS inside /Contents, the certificates and the exact /ByteRange coverage.

3. 3

   Read the verdict cards — signer, certificate, cryptographic check, tamper detection — and download the plain-text verification report.

Frequently asked