You were sent a signed PDF and want to know whether it is genuine. This reads only — it never signs — and reports three independent facts, because "the signature is valid" does not mean "the document is trustworthy".
This one needs an upload, and is deleted afterwards
Browsers cannot do this calculation, so the file goes to our server. It is deleted automatically 60 minutes after the job finishes, and the working copy lives in a memory filesystem that is wiped whenever the server restarts.
We do not log file names and do not log file contents — that is a hard rule in our engineering standards, not a setting.
What it does — and what it doesn't
The three answers are separate: ① cryptographic integrity — has anything changed since signing; ② coverage — was the whole document signed or only part of it; ③ certificate chain trust — who signed it, and can that certificate be trusted.
With no trust root supplied, the answer is always "not trusted". Anyone can generate a self-signed certificate, so we will not call something trustworthy merely because a signature exists.
Verification only — this tool touches no private key.
The signature has to be a real PDF digital signature. A pasted picture of a signature produces nothing, because it never was one.
Common questions
Why split it into three?
Because they are three things. A document can be unmodified but signed by someone you have no reason to trust, or validly signed but only across the first three pages. One green tick would mislead.
What is a trust root?
Whose certificates you have decided to believe. Government and corporate certificate authorities publish them. Without one, treat the result as information, not proof.
Does my file leave my computer?
It is uploaded for processing and deleted after 60 minutes. Verification makes no outbound connections and checks no revocation lists.
