# PDF Signature Checker

Inspect the digital signatures embedded in a PDF.

## URL

https://ilham.dev/tools/pdf-signature-checker/

## What It Does

Read a PDF and report the signatures it contains: who signed, when, and whether the byte range each signature covers still matches the file. It walks the PDF structure directly, with no upload and no external library.

## Features

- Runs in the browser
- No login required

## Input

text input.

## Output

text output.

## Privacy

Processing happens locally in the browser.

No input data is uploaded to ilham.dev.

- Requires login: false
- Requires API key: false
- Stores user data: false


## Examples

- Does this prove the signer's identity?
- Why is a signature reported as invalid?




## Questions

### Does this prove the signer's identity?

No. Even an **Intact** digest here does not verify the public-key signature or trust the certificate. Use a full verifier and independent identity checks when it matters.

### Why is a signature reported as invalid?

A mismatch can mean the signed byte range changed, or that the format or range was not interpreted as expected. **Could not verify** can also mean an unsupported digest. Do not infer the cause or the signer's identity from this lightweight result alone.