PDF Signature Checker

PDF Signature Checker scans a PDF file's internal structure for digital signature fields — the dictionaries a PDF stores when it's been signed with a certificate-based digital signature (as opposed to a scanned or drawn signature image, which leaves no structural trace). When found, it surfaces whatever metadata is present in plain text: the signer's stated name, reason, location, and signing time, along with the signature/hash algorithm reported.

Important: this is a lightweight structural check, not a cryptographic verifier. It confirms that signature fields exist and shows their metadata, but it does not validate the actual cryptographic signature, check it against a trusted certificate authority, or confirm the document hasn't been altered since signing — that requires a full PDF signature-validation library (or opening the file in Adobe Acrobat / a similar tool that shows the "Signature Panel"). Treat a "found" result as "this PDF claims to be signed," not "this signature is valid."

Version 1.0.0