Digital Signatures

from ironpdf import *

# Cryptographically sign an existing PDF in 1 line of code!
PdfSignature(r".\certificates\IronSoftware.p12", "123456").SignPdfFile("any.pdf")

##### Advanced example for more control #####

# Step 1. Create a PDF
renderer = ChromePdfRenderer()
doc = renderer.RenderHtmlAsPdf("<h1>Testing 2048 bit digital security</h1>")

# Step 2. Create a Signature.
# You may create a .pfx or .p12 PDF signing certificate using Adobe Acrobat Reader.
# Read: https://helpx.adobe.com/acrobat/using/digital-ids.html
signature = PdfSignature(r"certificates\IronSoftware.pfx", "123456")

# Step 3. Optional signing options and a handwritten signature graphic
signature.SigningContact = "support@ironsoftware.com"
signature.SigningLocation = "Chicago, USA"
signature.SigningReason = "To show how to sign a PDF"

# Step 4. Sign the PDF with the PdfSignature. Multiple signing certificates may be used
doc.Sign(signature)

# Step 5. The PDF is not signed until saved to file, steam or byte array.
doc.SaveAs("signed.pdf")

Digital Signatures

This Python code demonstrates how to use a PDF library, such as PyPDF2, to cryptographically sign an existing PDF and create a PDF with a digital signature.

How to Generate a Digital Signature in Python

Download a Python module to generate a digital signature.
You can use libraries like PyPDF2 and PyPDF4, which are Python libraries for reading and writing PDF files, but for signing you might prefer something like reportlab in combination with PyPDF2 for digital signatures.
Render a new PDF document.
Use reportlab to create a new PDF or modify an existing one.
Instantiate the PdfSignature class and import the digital certificate.
The code snippet below shows how you might do it using a hypothetical PdfSignature class. Replace it with the actual method of adding a signature from the library you choose.
Add additional information as needed.
Specify metadata, appearance, or location for the signature.
Use the sign method to sign the document.
Below is a Python code using reportlab to create a PDF and PyPDF2 to attach a digital signature.

from reportlab.pdfgen import canvas
from PyPDF2 import PdfWriter, PdfReader

# Create a new PDF document using reportlab
c = canvas.Canvas("unsigned_document.pdf")
c.drawString(100, 750, "This is a digitally unsigned document.")
c.save()

# Hypothetically instantiate PdfSignature - replace with actual implementation
# You may need to use another library or mix several tools, depending on requirements
def sign_pdf(input_pdf_path, output_pdf_path, cert_path, cert_password):
    """
    Sign the PDF file using a digital certificate.

    :param input_pdf_path: Path to the input PDF file
    :param output_pdf_path: Path to store the signed PDF
    :param cert_path: Path to the digital certificate file
    :param cert_password: Password for the digital certificate
    """
    # Read the PDF to be signed
    with open(input_pdf_path, "rb") as input_pdf_file:
        reader = PdfReader(input_pdf_file)

        # Prepare the writer
        writer = PdfWriter()

        for page in reader.pages:
            writer.add_page(page)

        # Normally you have to create a signature object or use a library method
        # This is a pseudocode representing the signing logic
        writer.add_signature(cert_path, cert_password, location="Location", reason="Reason")

        # Write the signed PDF
        with open(output_pdf_path, "wb") as output_pdf_file:
            writer.write(output_pdf_file)

# Example usage
sign_pdf("unsigned_document.pdf", "signed_document.pdf", "path/to/certificate.pem", "password")

from reportlab.pdfgen import canvas
from PyPDF2 import PdfWriter, PdfReader

# Create a new PDF document using reportlab
c = canvas.Canvas("unsigned_document.pdf")
c.drawString(100, 750, "This is a digitally unsigned document.")
c.save()

# Hypothetically instantiate PdfSignature - replace with actual implementation
# You may need to use another library or mix several tools, depending on requirements
def sign_pdf(input_pdf_path, output_pdf_path, cert_path, cert_password):
    """
    Sign the PDF file using a digital certificate.

    :param input_pdf_path: Path to the input PDF file
    :param output_pdf_path: Path to store the signed PDF
    :param cert_path: Path to the digital certificate file
    :param cert_password: Password for the digital certificate
    """
    # Read the PDF to be signed
    with open(input_pdf_path, "rb") as input_pdf_file:
        reader = PdfReader(input_pdf_file)

        # Prepare the writer
        writer = PdfWriter()

        for page in reader.pages:
            writer.add_page(page)

        # Normally you have to create a signature object or use a library method
        # This is a pseudocode representing the signing logic
        writer.add_signature(cert_path, cert_password, location="Location", reason="Reason")

        # Write the signed PDF
        with open(output_pdf_path, "wb") as output_pdf_file:
            writer.write(output_pdf_file)

# Example usage
sign_pdf("unsigned_document.pdf", "signed_document.pdf", "path/to/certificate.pem", "password")

PYTHON

Note: Signing a PDF with a digital signature using reportlab and PyPDF2 is a complex process that may involve different libraries depending on the specific requirements. Ensure you have the necessary certificates and understanding of cryptographic principles while implementing this.