PDF digital signature and timestamp are the best ways to protect your PDF files from being forged. Syncfusion Essential PDF is a .NET PDF library that helps you add digital signature and time stamp to your PDF files in any .NET application, whether it is on Windows Forms, WPF, ASP.NET (web forms, MVC, Core), or even UWP, Xamarin.Forms, Xamarin.Android, and Xamarin.iOS. Syncfusion provides many ways to digitally sign a document: X509 certificates, such as .pfx files with private keys and also supports hardware security modules (HSM), Online Certificate Status Protocol (OCSP), certificate revocation lists (CRL), and Windows Certificate Store for authenticity and integrity.
The Syncfusion .NET PDF library provides a completely customizable appearance for its e-signature. The content of the signature can be images, texts, graphics, and shapes.
LTV signatures allow you to check the validity of a signature long after signing the document. All the required elements for signature validation must be embedded in the signed PDF to use LTV.
It is possible to include the date and time of your signing the PDF as part of your certificate-based digital signature. A timestamp helps you establish when you signed the PDF and reduces the chance of an invalid signatures. Syncfusion Essential PDF makes time-stamping a PDF document possible with only a few lines of code.
You can also get or retrieve the digitally signed certificate details like subject, author, and expiry date. Based on the expiry date, you can digitally sign the PDF with valid certificate again.
Easily add the digital signature to a PDF document using a few simple lines of C# code as demonstrated below. Also explore our .NET PDF Example that shows how to create and modify PDF files from C# with 5 lines of code on different platforms.
using Syncfusion.Pdf; //Creates a new PDF document PdfDocument document = new PdfDocument(); //Adds a new page PdfPageBase page = document.Pages.Add(); PdfGraphics graphics = page.Graphics; //Creates a certificate instance from PFX file with private key PdfCertificate pdfCert = new PdfCertificate(@"PDF.pfx", "syncfusion"); //Creates a digital signature PdfSignature signature = new PdfSignature(document, page, pdfCert, "Signature"); //Sets an image for signature field PdfBitmap signatureImage = new PdfBitmap(@"signature.jpg"); //Sets signature information signature.Bounds = new RectangleF(new PointF(0, 0), signatureImage.PhysicalDimension); signature.ContactInfo = "email@example.com"; signature.LocationInfo = "Honolulu, Hawaii"; signature.Reason = "I am author of this document."; //Draws the signature image graphics.DrawImage(signatureImage, 0, 0); //Saves and closes the document document.Save("Output.pdf"); document.Close(true);
Imports Syncfusion.Pdf 'Creates a new PDF document Dim document As New PdfDocument() 'Adds a new page Dim page As PdfPageBase = document.Pages.Add() Dim graphics As PdfGraphics = page.Graphics 'Creates a certificate instance from PFX file with private key Dim pdfCert As New PdfCertificate("PDF.pfx", "syncfusion") 'Creates a digital signature Dim signature As New PdfSignature(document, page, pdfCert, "Signature") 'Sets an image for signature field Dim signatureImage As New PdfBitmap("signature.jpg") 'Sets signature info signature.Bounds = New RectangleF(New PointF(0, 0), signatureImage.PhysicalDimension) signature.ContactInfo = "firstname.lastname@example.org" signature.LocationInfo = "Honolulu, Hawaii" signature.Reason = "I am author of this document." 'Draws the signature image graphics.DrawImage(signatureImage, 0, 0) 'Saves and closes the document document.Save("Output.pdf") document.Close(True)
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Syncfusion’s file format components helped me create the reports I needed, fast. – J. Pereira, Software Developer.
Syncfusion File Format Libraries - Manipulate Excel, Word, PowerPoint, and PDF files
Read and write Excel, Word, PDF, and PowerPoint files. Also includes integrated visualization capabilities. Advanced features include support for pivot tables, pivot charts, mail-merge, and extensive formatting.
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