How digitally sign a PDF document using the USB token in WF application?
The Syncfusion Essential® PDF is a feature-rich and high-performance .NET PDF library that is used to create, read, and edit PDF documents programmatically without Adobe dependencies. This library also offers functionality to merge, split, stamp, forms, compress, and secure PDF files. Using this library, you can digitally sign a PDF document using the Windows certificate store.
When the USB token is connected to the system, the certificates in the token are added automatically to the Windows Certificate Store under the store name “My”. To sign the document using a certificate installed on the USB token you need to know the issuer common name & the serial number of the certificate, and a valid password or PIN to access the USB token. After that, you can digitally sign a PDF document using the Windows certificate store.
Steps to digitally sign a PDF document using the Windows certificate store:
1. Create a new C# console application project.
2. Install the Syncfusion.PDF.WinForms NuGet packages as a reference to your .NET Framework application from the NuGet.org.
3. Include the following namespaces in the Program.cs file.
C#
using Syncfusion.Pdf.Parsing; using Syncfusion.Pdf.Security; using System.Security.Cryptography.X509Certificates;
VB.NET
Imports Syncfusion.Pdf.Parsing Imports Syncfusion.Pdf.Security Imports System.Security.Cryptography.X509Certificates
4. The following code example shows how to create a PDF digital signature in C# using a Windows certificate store.
C#
//Initialize the Windows store.
X509Store store = new X509Store("MY", StoreLocation.CurrentUser);
store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
X509Certificate2Collection collection = (X509Certificate2Collection)store.Certificates;
//Find the certificate using thumb print.
X509Certificate2Collection fcollection = (X509Certificate2Collection)collection.Find(X509FindType.FindByThumbprint, "F85E1C5D93115CA3F969DA3ABC8E0E9547FCCF5A", true);
X509Certificate2 digitalID = collection[0];
//Load an existing PDF document.
PdfLoadedDocument document = new PdfLoadedDocument("PDF_Succinctly.pdf");
//Load X509Certificate2.
PdfCertificate certificate = new PdfCertificate(digitalID);
//Create a revision 2 signature with a loaded digital ID.
PdfSignature signature = new PdfSignature(document, document.Pages[0], certificate, "DigitalSignature");
signature.Bounds = new RectangleF(50,350, 100, 40);
//Changing the digital signature standard and hashing algorithm.
signature.Settings.CryptographicStandard = CryptographicStandard.CADES;
signature.Settings.DigestAlgorithm = DigestAlgorithm.SHA512;
//Save the PDF document.
document.Save("WindowsStore.pdf");
//Close the document.
document.Close(true);
VB.NET
'Initialize the Windows store.
Dim store As X509Store = New X509Store("MY", StoreLocation.CurrentUser)
store.Open(OpenFlags.[ReadOnly] Or OpenFlags.OpenExistingOnly)
'Find the certificate using thumb print.
Dim collection As X509Certificate2Collection = CType(store.Certificates, X509Certificate2Collection)
Dim fcollection As X509Certificate2Collection = CType(collection.Find(X509FindType.FindByThumbprint, "F85E1C5D93115CA3F969DA3ABC8E0E9547FCCF5A", True), X509Certificate2Collection)
Dim digitalID As X509Certificate2 = collection(0)
'Load existing PDF document.
Dim document As PdfLoadedDocument = New PdfLoadedDocument("PDF_Succinctly.pdf")
'Load X509Certificate2.
Dim certificate As PdfCertificate = New PdfCertificate(digitalID)
'Create a revision 2 signature with loaded digital ID.
Dim signature As PdfSignature = New PdfSignature(document, document.Pages(0), certificate, "DigitalSignature")
'Changing the digital signature standard and hashing algorithm.
signature.Settings.CryptographicStandard = CryptographicStandard.CADES
signature.Settings.DigestAlgorithm = DigestAlgorithm.SHA512
'Save the PDF document.
document.Save("WindowsStore.pdf")
'Close the document.
document.Close(True)
A complete working sample can be downloaded from the digitally sign a pdf document using a window store sample.
By executing the program, you will get the PDF document as follows.
Refer here to explore the rich set of Syncfusion Essential® PDF features.
Starting with v16.2.0.x, if you reference Syncfusion® assemblies from trial setup or the NuGet feed, include a license key in your projects. Refer to the link to learn about generating and registering the Syncfusion® license key in your application to use the components without trail message.
See Also:
https://www.syncfusion.com/blogs/post/create-validate-pdf-digital-signatures-csharp.aspx
Conclusion
I hope you enjoyed learning about how digitally sign a PDF document using the USB token in WF application.
You can refer to our .NET PDF feature tour page to know about its other groundbreaking feature representations and documentation, and how to quickly get started for configuration specifications. You can also explore our PDF example to understand how to create and manipulate data.
For current customers, you can check out our Document processing libraries from the License and Downloads page. If you are new to Syncfusion®, you can try our 30-day free trial to check out our ASP.NET Core File Format PDF and other .NET Corcontrols.
If you have any queries or require clarifications, please let us know in the comments section below. You can also contact us through our support forums, Direct-Trac, or feedback portal. We are always happy to assist you!
