Signature Extraction

Aspose.PDF for Python via .NET provides the PdfFileSignature facade for inspecting and extracting data from signed PDF documents. After a PDF has been signed, you can use it to export signature resources such as the visual signature image and the certificate associated with the signature.

This example demonstrates two common extraction tasks:

1. Extract the visual image associated with a signature.
2. Extract the signing certificate from a signed PDF.

Extract a signature image

Use this method when the PDF contains a visible signature and you want to export its image data. The example opens the signed document, gets the first available signature name, extracts the image stream, and writes it to a file.

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


def extract_signature_image(infile, outfile):
    pdf_signature = create_pdf_file_signature(infile)
    try:
        sign_name = require_signature_name(pdf_signature)
        signature_image = pdf_signature.extract_image(sign_name)
        write_stream_data(signature_image, outfile)
    finally:
        pdf_signature.close()

Extract a signature certificate

Use extract_certificate() when you need the certificate data attached to a signature. This is useful for inspection, validation workflows, or storing the signer certificate separately from the PDF document.

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


def extract_signature_certificate(infile, outfile):
    pdf_signature = create_pdf_file_signature(infile)
    try:
        sign_name = require_signature_name(pdf_signature)
        signature_certificate = pdf_signature.extract_certificate(sign_name)
        write_stream_data(signature_certificate, outfile)
    finally:
        pdf_signature.close()