Digital signatures in pdf file

Question

hi how to add digital signatures in pdf file in c#

Bharat Vasant · Answer

If you are looking for Digitally Signing PDF file from Web Application (ASP.NET Application) using USB Token connected to client's device through web browser, here is the complete source code of the VS 2015 or VS 2017 project. http://help.signer.digital/digital_signing_and_authentication_from_web_browser.htm Free Online PDF Signing Software is at https://web.signer.digital

Atir Tahir · Answer

Use GroupDocs.Signature for .NET in order to sign a PDF document programmatically. using (Signature signature = new Signature( "sample.pdf" )) { // initialize digital option with certificate file path DigitalSignOptions options = new DigitalSignOptions( "certificate.pfx" ) { // optional: setup image file path ImageFilePath = "sample.jpg" , // set signature position Left = 100, Top = 100, // set Password = "1234567890" }; signature.Sign( "sampleSigned.pdf" , options); } In case of any issue, raise it on free support forum https://forum.groupdocs.com/

Chittaranjan Swain · Answer

Hi pankaj, Refer below links, https://www.gemboxsoftware.com/pdf/examples/c-sharp-vb-net-pdf-digital-signature/1102 https://www.codeproject.com/Questions/318495/Digital-Signatures-and-PDF-Documents-csharp https://www.sautinsoft.com/products/document/examples/digital-signature-net-csharp-vb.php

Gajendra Jangid · Answer

hello pankaj, Please have a look at below link: https://www.codeproject.com/Articles/14488/E-signing-PDF-documents-with-iTextSharp

Mohamed Abedallah · Answer

You can use LEADTOOLS to sign a PDF document using a certificate, and also verify an existing signature in a PDF file. To sign a file, you can use the PDFFile.SignDocument method. The code looks like this: PDFFile document = new PDFFile(sourceFileName); document.SignDocument( destinationFileName, signatureFileName, signaturePassword); Note that the “signatureFileName” is the file containing the digital signature. This should be a valid PFX file and cannot be null. To check if there's a signature in an existing PDF file, the code will be similar to this: private static bool ContainsSignature( string pdfFileName) { PDFDocument document = new PDFDocument(pdfFileName); PDFParsePagesOptions options = PDFParsePagesOptions.Signatures; document.ParsePages(options, 1, -1); foreach (PDFDocumentPage page in document.Pages) { IList objects = page.Objects; if (objects != null ) return true ; } return false ; } To verify a signature and see if it's valid, there are details in this help topic: https://www.leadtools.com/help/leadtools/v20/dh/pdf/pdfsignature.html

Leon D · Answer

You can use Spire.PDF to add digital signature to pdf in C#. 1. Install Spire.PDF from NuGet: https://www.nuget.org/packages/Spire.PDF/ 2. Use code like below: PdfDocument doc = new PdfDocument(@ "..\..	est.pdf" ); PdfCertificate cert = new PdfCertificate(@ "..\..\Demo.pfx" , "e-iceblue" ); var signature = new PdfSignature(doc, doc.Pages[0], cert, "Requestd1" ); signature.Bounds = new RectangleF( new PointF(280, 600), new SizeF(260, 90)); signature.IsTag = true ; signature.DigitalSignerLable= "Digitally signed by" ; signature.DigitalSigner = "Harry Hu for Test" ; signature.DistinguishedName = "DN:" ; signature.LocationInfoLabel = "Location:" ; signature.LocationInfo = "London" ; signature.ReasonLabel = "Reason: " ; signature.Reason = "Le document est certifie" ; signature.DateLabel = "Date: " ; signature.Date = DateTime.Now; signature.ContactInfoLabel = "Contact: " ; signature.ContactInfo = "123456789" ; signature.Certificated = false ; signature.ConfigGraphicType = ConfiguerGraphicType.Picture; signature.ConfiguerGraphicPath = "..\..\img1.png" ; signature.DocumentPermissions = PdfCertificationFlags.ForbidChanges; doc.SaveToFile( "sample.pdf" ); For more information, visit this link: https://www.e-iceblue.com/Tutorials/Spire.PDF/Spire.PDF-Program-Guide/PDF-Security/Create-Visible-Digital-Signature-in-PDF-with-C-Code.html

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