Get Signature Properties from PDF in C# and .NET

In the digital world, ensuring the authenticity and integrity of documents is paramount. Digital signatures serve this purpose by providing a secure and verifiable means of signing documents. In C# and .NET, developers can easily read digital signature properties from PDF documents, which can be crucial for validation and auditing purposes.

This article will guide you through the process of accessing digital signature information in using Sautinsoft.PDF .Net library.

To read digital signature properties from a PDF document, follow these steps:

  1. Add SautinSoft.PDF from NuGet.
  2. Load a PDF document.
  3. Find the digital signature field and read the contents: name, date, location, reason, contact information.
  4. Read the contents of the certificate.

Input file: simple text.pdf

Output result:

By following the steps outlined above, developers can programmatically access and validate digital signatures, which is essential for document verification processes.

Complete code

using System;
using System.IO;
using Org.BouncyCastle.X509;
using SautinSoft;
using SautinSoft.Pdf;
using SautinSoft.Pdf.Content;
using SautinSoft.Pdf.Forms;

namespace Sample
{
    class Sample
    {
        /// <summary>
        /// Read digital signature properties from a PDF document using C# and .NET
        /// </summary>
        /// <remarks>
        /// Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/read-digital-signature-properties-from-a-pdf-document-using-csharp-dotnet.php
        /// </remarks>
        static void Main(string[] args)
        {
            // Before starting this example, please get a free 100-day trial key:
            // https://sautinsoft.com/start-for-free/

            // Apply the key here:
            // PdfDocument.SetLicense("...");

            string inpFile = Path.GetFullPath(@"..\..\..\digital signature.pdf");            

            using (PdfDocument document = PdfDocument.Load(inpFile))
            {
                var field = document.Form.Fields.FirstOrDefault(f => f is PdfSignatureField);
                if (field != null && field is PdfSignatureField signField)
                {
                    Console.WriteLine($"Name: {signField.Value.Name}.");
                    Console.WriteLine($"Date: {signField.Value.Date}.");
                    Console.WriteLine($"Location: {signField.Value.Location}.");
                    Console.WriteLine($"Reason: {signField.Value.Reason}.");
                    Console.WriteLine($"ContactInfo: {signField.Value.ContactInfo}.");

                    var content = signField.Value.Content;
                    X509Certificate certificate = new X509Certificate(content.SignerCertificate.GetRawData());
                    Console.WriteLine("SignerCertificate data:");
                    Console.WriteLine(certificate);
                }
                else
                {
                    Console.WriteLine("The PDF doesn't have a digital signature!");
                }
            }
        }
    }
}

Download

If you need a new code example or have a question: email us at support@sautinsoft.com or ask at Online Chat (right-bottom corner of this page) or use the Form below:


Questions and suggestions from you are always welcome!

We are developing .Net components since 2002. We know PDF, DOCX, RTF, HTML, XLSX and Images formats. If you need any assistance with creating, modifying or converting documents in various formats, we can help you. We will write any code example for you absolutely free.