Sign Document with Digital Signature Leave feedback

In today’s digital age, ensuring the authenticity and integrity of electronic documents is crucial. One highly effective method for achieving this is through the use of digital signatures. In this guide, we will explore the world of digital signatures, explaining what they are, why they are essential, and how you can utilize GroupDocs.Signature for Python via .NET to seamlessly eSign your documents.

A digital signature is a cryptographic mechanism for verifying the authenticity and integrity of electronic documents. It provides strong assurance that the document originated from a known sender and has not been tampered with by unauthorized sources. Digital signatures are typically represented by certificates containing private (for signing) and public (for verification) keys. Various public key cryptography standards, such as PFX format, are commonly used for this purpose. The picture below shows how a digital signature looks on a PDF document page by default.

• Enhanced Security: Digital signatures provide a higher level of document security, making it extremely challenging for unauthorized parties to alter the content.
• Authentication: They offer a reliable way to verify the identity of the document sender.
• Non-repudiation: Digital signatures prevent senders from denying the authenticity of the signed document.

GroupDocs.Signature for Python via .NET supports the creation of digital signatures based on existing PFX certificates. To specify various settings the library provides the DigitalSignOptions class that allows adjusting digital signature properties in the document:

• The certificate_file_path or certificate_stream properties define the certificate source;
• The password property specifies the certificate password;
• The contact, reason and location properties specify additional descriptions;
• The visible property specifies whether the signature should be visible on the document page or not;
• The xades_type property defines whether the e-signature should be of an XML Advanced Electronic Signature type.

1. Install the GroupDocs.Signature package using pip:

pip install groupdocs-signature

2. Create a new instance of the Signature class and pass the source document path as a constructor parameter.
3. Instantiate the DigitalSignOptions object with the required certificate and its password.
4. Call the Sign method of the Signature class instance and pass the DigitalSignOptions to it.

The example below shows how to sign a PDF document with a digital e-signature using Python. We can sign any other supported document format in the same way.

import groupdocs.signature as signature
from groupdocs.signature.options import DigitalSignOptions

# Initialize signature
with signature.Signature("sample.pdf") as sign:
    # Create digital signature options
    options = DigitalSignOptions("certificate.pfx")
    
    # Set certificate password
    options.password = "1234567890"
    
    # Optional: setup image file path
    options.image_file_path = "sample.jpg"
    
    # Set signature position
    options.left = 100
    options.top = 100
    
    # Sign document
    sign.sign("sampleSigned.pdf", options)

You can customize the digital signature further with additional options:

import groupdocs.signature as signature
from groupdocs.signature.options import DigitalSignOptions

# Initialize signature
with signature.Signature("sample.pdf") as sign:
    # Create digital signature options
    options = DigitalSignOptions("certificate.pfx")
    
    # Set certificate password
    options.password = "1234567890"
    
    # Set signature appearance
    options.visible = True
    options.image_file_path = "signature.jpg"
    
    # Set signature position and size
    options.left = 100
    options.top = 100
    options.width = 200
    options.height = 100
    
    # Set additional information
    options.contact = "John Smith"
    options.reason = "Approval"
    options.location = "New York"
    
    # Set XAdES type
    options.xades_type = signature.XAdESType.XAdES
    
    # Sign document
    sign.sign("sampleSigned.pdf", options)

You can also load the certificate from a stream:

import groupdocs.signature as signature
from groupdocs.signature.options import DigitalSignOptions

# Initialize signature
with signature.Signature("sample.pdf") as sign:
    # Load certificate from stream
    with open("certificate.pfx", "rb") as cert_stream:
        # Create digital signature options
        options = DigitalSignOptions(cert_stream)
        
        # Set certificate password
        options.password = "1234567890"
        
        # Set signature position
        options.left = 100
        options.top = 100
        
        # Sign document
        sign.sign("sampleSigned.pdf", options)

This guide demonstrates how to use GroupDocs.Signature for Python via .NET to sign documents with digital signatures. It explains how to load documents, configure certificate-based signatures, and save signed files securely. Advanced features, including signature appearance customization and validation, are also covered. Refer to related resources for additional details on digital signing workflows.

You may easily run the code above and see the feature in action in our GitHub examples:

• GroupDocs.Signature for Python via .NET examples

Along with the full-featured Python library, we provide simple but powerful free online apps.

To sign PDF, Word, Excel, PowerPoint, and other documents you can use the online apps from the GroupDocs.Signature App Product Family.