how to add digital signature in pdf using asp net c# without mvc. I want full code as I am new to asp.net

Question

Hello,

I want to upload pdf file. After uploading file, I want to sign that pdf file using my Digital Certificate which is in Pen Drive format attached to my Computer.

Answer 1

Hi @Tarang Rohit ,
You could add a digital signature to a pdf document using SelectPdf Library for .NET.

protected void BtnCreatePdf_Click(object sender, EventArgs e)  
        {  
            // create a new pdf document  
            PdfDocument doc = new PdfDocument();  
  
            // add a new page to the document  
            PdfPage page = doc.AddPage();  
  
            // get image path   
            // the image will be used to display the digital signature over it  
            string imgFile = Server.MapPath("~/files/logo.png");  
  
            // get certificate path  
            string certFile = Server.MapPath("~/files/selectpdf.pfx");  
  
            // define a rendering result object  
            PdfRenderingResult result;  
  
            // create image element from file path   
            PdfImageElement img = new PdfImageElement(0, 0, imgFile);  
            result = page.Add(img);  
  
            // get the #PKCS12 certificate from file  
            PdfDigitalCertificatesCollection certificates =   
                PdfDigitalCertificatesStore.GetCertificates(certFile, "selectpdf");  
            PdfDigitalCertificate certificate = certificates[0];  
  
            // create the digital signature object  
            PdfDigitalSignatureElement signature =   
                new PdfDigitalSignatureElement(result.PdfPageLastRectangle, certificate);  
            signature.Reason = "SelectPdf";  
            signature.ContactInfo = "SelectPdf";  
            signature.Location = "SelectPdf";  
            page.Add(signature);  
  
            // save pdf document  
            doc.Save(Response, false, "Sample.pdf");  
  
            // close pdf document  
            doc.Close();  
        }  

Best regards,
Yijing Sun

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.