Sign PDF using Aspose.PDF for Python via .NET

An electronic digital signature is a form of e-signature employing cryptographic techniques to ensure data integrity and identify the signatory. It’s generated by encrypting electronic data with a private key and verified with a public key. This signature is vital for verifying the authenticity of the document signer, and the digitally signed electronic copy is considered the original. It’s a key element of the public key infrastructure (PKI).

To include a digital signature in a PDF file, you can employ the Aspose.PDF for .NET API. This API is crafted to deliver a feature-rich, robust, and user-friendly document manipulation capability for Python through .NET. Installation is straightforward via the NuGet package manager, or you can use the following command in the Package Manager Console.

pip install aspose-pdf

The following Python code sample utilizes the Aspose.PDF for .NET library to digitally sign a PDF document using a PKCS7 certificate. The input PDF file is named “DigitallySign.pdf,” and the resulting signed PDF file is named “DigitallySign_out.pdf.”

The code leverages the Aspose.PDF Document class to load the input PDF file and then creates a PdfFileSignature object for performing the digital signature operation. This operation adheres to the PKCS7 standard and involves a certificate file named “test.pfx” located in the “C:\Keys” directory, along with its associated password “Pa$$w0rd2020.”

The signature is added to the first page of the input PDF document, positioned within a signature rectangle defined by coordinates (300, 100) and (400, 200). Lastly, the digitally signed PDF is saved as the output file.

inFile = "DigitallySign.pdf"
    outFile = "DigitallySign_out.pdf"
    document = Document(inFile)
    signature = PdfFileSignature(document)
    # Use PKCS7/PKCS7Detached objects
    pkcs = new PKCS7("C:\\Keys\\test.pfx", "Pa$$w0rd2020")
 
    signature.Sign(1, true, Rectangle(300, 100, 400, 200),pkcs)
    # Save output PDF file
    signature.Save(outFile);

The digital signature application is designed for the quick and easy addition of a digital signature to your PDF document. You can use this online web application to add a digital signature online for free.

Aspose.PDF for .NET is a robust and dependable library that enables developers to integrate extensive PDF processing capabilities into their applications. This API allows the development of 32-bit and 64-bit applications for tasks such as PDF generation, reading, conversion, and manipulation, all without the need for Adobe Acrobat.

To discover additional functionalities provided by the Aspose.PDF for the .NET library, please refer to the documentation. If you encounter specific issues or require assistance, our forum is available for resolving particular cases.

This article explains how to include a digital signature in a PDF document using Aspose.PDF for .NET and a free online tool. Aspose.PDF for .NET offers a comprehensive set of functions for handling digital signatures programmatically, while the online tool offers a simple, code-free method for adding signatures. Whether you favor a coding approach or a non-programmatic one, adding a digital signature to a PDF is easily achievable.