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PDF Signature Checker

DataDeveloperSecurity

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INPUT

Auto Process

OUTPUT

Client Side

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Guide

PDF Signature Checker

Verify and inspect digital signatures embedded in PDF files. This tool parses PDF documents directly in your browser to detect and display information about any digital signatures, including signer name, signing date, certificate details, and byte range coverage.

How to Use

Upload a PDF file using the file uploader. The tool will automatically analyze the document and display all digital signatures found. For each signature, you will see the signer name, signing date, filter type, reason, location, and byte range coverage information.

Features

Client-Side Processing – Your PDF never leaves your browser. All analysis is performed locally for maximum privacy.
Signature Detection – Finds all /Type /Sig dictionaries in the PDF structure to identify digital signatures.
Detailed Information – Displays signer name, date, filter, sub-filter, reason, location, and contact info.
Byte Range Analysis – Shows the signed byte range and whether the signature covers the entire document.

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 FAQ

What is a digital signature in a PDF?

A digital signature in a PDF is a cryptographic mechanism that verifies the identity of the signer and ensures the document has not been tampered with after signing. It uses public key infrastructure (PKI) with a certificate issued by a trusted authority.
What is a PDF ByteRange and why does it matter?

The ByteRange in a PDF signature specifies which bytes of the file are covered by the cryptographic hash. A signature that covers the entire document ensures no content was modified after signing. Partial coverage may indicate that changes were made to the document after the signature was applied.