Crypto
PDF Signature Checker
Look for signature dictionaries and ByteRange declarations in a PDF without confusing their presence with a trusted digital signature.
About this tool
When to use it
Look for signature dictionaries and ByteRange declarations in a PDF without confusing their presence with a trusted digital signature.
How to use it
Choose a PDF, read the detected structure count and byte-range report, then use a full PDF signature validator when trust or document integrity must be established. Share the report only after checking filename and signer-field details.
Guide updated . Examples checked against this implementation.
Worked examples
A minimal unsigned test fixture
Input
A PDF fixture beginning %PDF-1.7 with no /Type /Sig or /ByteRange entriesExpected output
No signature data detectedThis means the scanner did not find its recognized markers. It does not prove that every possible PDF structure was understood.
Errors and unsupported input
A file with a .pdf extension has no PDF headerChoose actual PDF bytes. Renaming another file does not turn it into a PDF.
Continue this workflow
- Base64 File Converter: Represent file bytes as Base64 when preparing an integration fixture.
Questions
Frequently asked questions
Does Signature data detected mean the document is trustworthy?
No. The fields can be present without a valid or trusted signature. Validate with software that checks the cryptography and certificate chain.