Signature Verification

Aspose.PDF for Python via .NET provides the PdfFileSignature facade for validating signed PDF documents. After a PDF has been signed, you can use it to confirm that a signature is valid and to detect whether the document contains any signature entries.

This example demonstrates two common verification tasks:

1. Verify that an existing PDF signature is valid.
2. Check whether a PDF contains any signatures.

Verify a PDF signature

Use verify_signature() when you need to validate a specific signature in the document. The example resolves the first available signature name and verifies whether that signature is valid.

import aspose.pdf.facades as pdf_facades
import sys
from os import path


def verify_pdf_signature(infile):
    pdf_signature = create_pdf_file_signature(infile)
    try:
        sign_name = require_signature_name(pdf_signature)
        is_valid = pdf_signature.verify_signature(sign_name)
        print(f"Signature '{sign_name}' is valid: {is_valid}")
    finally:
        pdf_signature.close()

Check whether a PDF contains signatures

Use contains_signature() when you only need to know whether the PDF includes any signatures at all. This is useful as a quick check before running more detailed verification or extraction logic.

import aspose.pdf.facades as pdf_facades
import sys
from os import path


def check_if_pdf_contains_signatures(infile):
    pdf_signature = create_pdf_file_signature(infile)
    try:
        contains_signatures = pdf_signature.contains_signature()
        print(f"PDF contains signatures: {contains_signatures}")
    finally:
        pdf_signature.close()