Sign PDF with PKCS # 11

Situation:

The card is an identity card that has a pin so I need to use a form that allows me to sign the PDF with a reader requesting a pin that can then validate that PDF if it is signed.

I was making an application with APDU commands but the Digital signature as a PDF property is much harder than signing a hash.

They gave me the possibility that PKCS # 11 is much easier but I can not make it work.

PKCS page # 11

I can not determine where to grab that DLL

// Specify path to the unmanaged PCKS#11 library
        string libraryPath = @"siecap11.dll";

Sample Signature

public void SignPdfDocument()
    {
        // Specify path to the unsigned PDF that will be created by this code
        string unsignedPdfPath = @"c:\Test\unsigned.pdf";

        // Specify path to the signed PDF that will be created by this code
        string signedPdfPath = @"c:\Test\signed.pdf";

        // Create simple PDF document with iText
        using (Document document = new Document(PageSize.A4, 50, 50, 50, 50))
        {
            using (FileStream outputStream = new FileStream(unsignedPdfPath, FileMode.Create))
            {
                using (PdfWriter pdfWriter = PdfWriter.GetInstance(document, outputStream))
                {
                    document.Open();
                    document.Add(new Paragraph("Hello World!"));
                    document.Close();
                }
            }
        }

        // Do something interesting with unsigned PDF document
        FileInfo unsignedPdfInfo = new FileInfo(unsignedPdfPath);
        Assert.IsTrue(unsignedPdfInfo.Length > 0);

        // Specify path to the unmanaged PCKS#11 library
        string libraryPath = @"siecap11.dll";

        // Specify serial number of the token that contains signing key. May be null if tokenLabel is specified.
        string tokenSerial = null;

        // Specify label of of the token that contains signing key. May be null if tokenSerial is specified
        string tokenLabel = @"Pkcs11Interop";

        // Specify PIN for the token
        string pin = @"11111111";

        // Specify label (value of CKA_LABEL attribute) of the private key used for signing. May be null if ckaId is specified.
        string ckaLabel = @"John Doe";

        // Specify hex encoded string with identifier (value of CKA_ID attribute) of the private key used for signing. May be null if ckaLabel is specified.
        string ckaId = null;

        // Specify hash algorihtm used for the signature creation
        HashAlgorithm hashAlgorithm = HashAlgorithm.SHA256;

        // Create instance of Pkcs11Signature class that allows iText to create PKCS#1 v1.5 RSA signature with the private key stored on PKCS#11 compatible device
        using (Pkcs11RsaSignature pkcs11RsaSignature = new Pkcs11RsaSignature(libraryPath, tokenSerial, tokenLabel, pin, ckaLabel, ckaId, hashAlgorithm))
        {
            // When signing certificate is stored on the token it can be usually read with GetSigningCertificate() method
            byte[] signingCertificate = pkcs11RsaSignature.GetSigningCertificate();

            // All certificates stored on the token can be usually read with GetAllCertificates() method
            List<byte[]> otherCertificates = pkcs11RsaSignature.GetAllCertificates();

            // Build certification path for the signing certificate
            ICollection<Org.BouncyCastle.X509.X509Certificate> certPath = CertUtils.BuildCertPath(signingCertificate, otherCertificates);

            // Read unsigned PDF document
            using (PdfReader pdfReader = new PdfReader(unsignedPdfPath))
            {
                // Create output stream for signed PDF document
                using (FileStream outputStream = new FileStream(signedPdfPath, FileMode.Create))
                {
                    // Create PdfStamper that applies extra content to the PDF document
                    using (PdfStamper pdfStamper = PdfStamper.CreateSignature(pdfReader, outputStream, '
// Specify path to the unmanaged PCKS#11 library
        string libraryPath = @"siecap11.dll";
', Path.GetTempFileName(), true))
                    {
                        // Sign PDF document
                        MakeSignature.SignDetached(pdfStamper.SignatureAppearance, pkcs11RsaSignature, certPath, null, null, null, 0, CryptoStandard.CADES);
                    }
                }
            }
        }

        // Do something interesting with the signed PDF document
        FileInfo signedPdfInfo = new FileInfo(signedPdfPath);
        Assert.IsTrue(signedPdfInfo.Length > signedPdfPath.Length);
    }

Thank you very much