Digital signature using HW token is using two timestamps

[xaero]

Hello,

I have created a small application in .net 8.0 to sign PDF documents with a certificate using a hardware token that requires a password via an authentication application. I am using FreeSpire.PDF 10.2.0. However, when I save the signed document file, the authentication application prompts me for the password twice and actually uses two timestamps (which are paid).

I have tried using the competing Syncfusion, where it works well.

I attach the code below:

Code: Select all

private async Task<Stream> SignPdf(Stream file)
{
    try
    {
        X509Store store = new X509Store(StoreLocation.CurrentUser);
        store.Open(OpenFlags.ReadOnly);
        X509Certificate2Collection certCollection = store.Certificates.Find(X509FindType.FindByThumbprint, _options.CertificateThumbprint, false);

        if (certCollection.Count == 0)
        {
            throw new Exception("Certificate not found!");
        }

        X509Certificate2 cert = certCollection[0];

        // Load the PDF document
        PdfDocument doc = new PdfDocument();
        doc.LoadFromStream(file);

        // Create a visible signature
        PdfCertificate pdfCert = new PdfCertificate(cert);
        PdfSignature pdfSignature = new PdfSignature(doc, doc.Pages[0], pdfCert, "signature");
        pdfSignature.GraphicsMode = GraphicMode.SignImageOnly;
        pdfSignature.SignImageLayout = SignImageLayout.Stretch;

        string assemblyPath = Path.GetDirectoryName(typeof(Program).Assembly.Location);
        var signatureImagePath = Path.Combine(assemblyPath, "Content", "signature.png");
        pdfSignature.SignImageSource = PdfImage.FromFile(signatureImagePath);
        pdfSignature.ConfigureTimestamp(_options.TimeStampServer, _options.TimeStampUser, _options.TimeStampPassword);

        var documentSize = doc.Pages[0].Size;

        var currentSignatureWidth = _options.SignatureWidth;
        var currentSignatureHeight = _options.SignatureHeight;

        if (documentSize.Width < currentSignatureWidth)
        {
            currentSignatureWidth = documentSize.Width - _options.SignatureMargin;
        }
        if (documentSize.Height < currentSignatureHeight)
        {
            currentSignatureHeight = documentSize.Height - _options.SignatureMargin;
        }

        pdfSignature.Bounds = new RectangleF(new PointF(documentSize.Width - currentSignatureWidth - _options.SignatureMargin, documentSize.Height - currentSignatureHeight - _options.SignatureMargin), new SizeF(currentSignatureWidth, currentSignatureHeight));

        // Save the signed PDF document
        doc.SaveToStream(file);
        return file;
    }
    catch (Exception ex)
    {
        throw new Exception("Error during signing of document.", ex);
    }
}


[Amin.Gan]

Hello,

Thank you for your inquiry. Our product also supports using custom external service to sign. You can refer to the following sample code and the attached files to set their parameters.


Code: Select all

PdfDocument doc = new PdfDocument();
doc.LoadFromFile(@"test.pdf");
X509Store store = new X509Store(StoreLocation. CurrentUser);
store.Open(OpenFlags. ReadOnly);
X509Certificate2Collection certs = store.Certificates.Find(X509FindType. FindByThumbprint,  "F9B500AD95CDA70CD5157C3A1DF8C35049C3BEF0", false);
X509Certificate2 cert = new X509Certificate2(certs[0]);
//create CustomPKCS7SignatureFormatterWithAPI
BugDebug.CustomPKCS7SignatureFormatterWithAPI customPKCS7SignatureFormatter = new BugDebug.CustomPKCS7SignatureFormatterWithAPI(cert);
PdfSignature signature = new PdfSignature(document: doc, page: doc.Pages[0], customPKCS7SignatureFormatter, signatureName: "test")
{
Bounds = new RectangleF(location: new PointF(x: 74, y: 635), size: new SizeF(width: 90, height: 158)),
};
signature.Certificated = true;
signature.DocumentPermissions = PdfCertificationFlags.AllowFormFill | PdfCertificationFlags.ForbidChanges;
doc.SaveToFile(@"out.pdf",  Spire.Pdf.FileFormat.PDF);
doc.Close();

If you have any other questions, please feel free to contact us at any time.

Sincerely,
Amin
E-iceblue support team