Sign a pdf using usb token

Question

I am using below code to sign a pdf using itextsharp version 5.5.1.0 . It works fine. But itextsharp 5.5.1.0
is having AGPL and i think it cannot be used in my application freely. But by using version below 4.1.6 which has GPL licence the same code does not work. So is there any alternative?
using System;
using System.Windows.Forms;
using System.IO;
using System.Security;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using iTextSharp.text.pdf;
using iTextSharp.text.pdf.security;
namespace SignPdf
public partial class Form1 : Form
public Form1()
InitializeComponent();
private SecureString GetSecurePin(string PinCode)
SecureString pwd = new SecureString();
foreach (var c in PinCode.ToCharArray()) pwd.AppendChar(c);
return pwd;
private void SignWithThisCert(X509Certificate2 cert)
string SourcePdfFileName = textBox1.Text;
string DestPdfFileName = textBox1.Text + "-Signed.pdf";
Org.BouncyCastle.X509.X509CertificateParser cp = new Org.BouncyCastle.X509.X509CertificateParser();
Org.BouncyCastle.X509.X509Certificate[] chain = new Org.BouncyCastle.X509.X509Certificate[] { cp.ReadCertificate(cert.RawData) };
IExternalSignature externalSignature = new X509Certificate2Signature(cert, "SHA-1");
PdfReader pdfReader = new PdfReader(SourcePdfFileName);
FileStream signedPdf = new FileStream(DestPdfFileName, FileMode.Create); //the output pdf file
PdfStamper pdfStamper = PdfStamper.CreateSignature(pdfReader, signedPdf, '\0');
PdfSignatureAppearance signatureAppearance = pdfStamper.SignatureAppearance;
//here set signatureAppearance at your will
signatureAppearance.Reason = "Because I can";
signatureAppearance.Location = "My location";
signatureAppearance.SignatureRenderingMode = PdfSignatureAppearance.RenderingMode.DESCRIPTION;
MakeSignature.SignDetached(signatureAppearance, externalSignature, chain, null, null, null, 0, CryptoStandard.CMS);
//MakeSignature.SignDetached(signatureAppearance, externalSignature, chain, null, null, null, 0, CryptoStandard.CADES);
MessageBox.Show("Done");
private void Form1_Load(object sender, EventArgs e)
private void button1_Click_1(object sender, EventArgs e)
//Sign with certificate selection in the windows certificate store
X509Store store = new X509Store(StoreLocation.CurrentUser);
store.Open(OpenFlags.ReadOnly);
X509Certificate2 cert = null;
//manually chose the certificate in the store
X509Certificate2Collection sel = X509Certificate2UI.SelectFromCollection(store.Certificates, null, null, X509SelectionFlag.SingleSelection);
if (sel.Count > 0)
cert = sel[0];
else
MessageBox.Show("Certificate not found");
return;
SignWithThisCert(cert);

Answer 1

hi.
you may return to the iTextshap version to 5.3.3, it works fine to sign a PDF using external USB token.
free C#
Excel  component being evaluated, any other recommendation is appreciated.
Thanks and Regards.
But version 5.3.3 is also having AGPL licence, As i said in question
version below 4.1.6 has GPL licence.