Itextsharp数字签名并在PDF上显示证书的信息(主题和发行者名称)作为附件图像 [英] Itextsharp Digital sign and show info(subject and issuername) of certificate on PDF as attached image

问题描述

我正在一个项目中使用iTextSharp对PDF文件进行数字签名，这是可行的，但是需要直接在PDF上显示证书的信息(请参阅附图)，如何执行或设置iTextSharp的任何参数?

I am working on one project using iTextSharp to digitally sign PDF file, it's workable, but need directly show the certificate's info on PDF (Please refer to attached image), how to do or set any parameter of iTextSharp?

    public static X509Certificate2 cert;
    //Sign with certificate selection in the windows certificate store
    public static void Sign(string pdfFile, string outPdfFile){
        Program.WriteLog("Signing Digital Certificate");            
        string IssuerName = null;
        X509Store store = new X509Store(StoreLocation.CurrentUser);
        store.Open(OpenFlags.ReadOnly);
        IssuerName = Properties.Settings.Default.IssuerName;
        if (IssuerName.Length > 0)
            cert = store.Certificates.Find(X509FindType.FindByIssuerName, IssuerName, false)[0];
        if (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
            {
                Console.WriteLine("Certificate not found");
                return;
            }
        }
        PdfReader reader = new PdfReader(pdfFile); // source pdf file
        FileStream os = new FileStream(outPdfFile, FileMode.Create);  //the output pdf file
        PdfStamper stamper = PdfStamper.CreateSignature(reader, os, '\0');
        stamper.SetEncryption(PdfWriter.STRENGTH128BITS, "", null, PdfWriter.AllowCopy | PdfWriter.AllowPrinting);
        try
        {
            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");
            PdfSignatureAppearance appearance = stamper.SignatureAppearance;
            //here set signatureAppearance at your will
            appearance.Reason = Properties.Settings.Default.DigitalSignReason;
            appearance.Location = Properties.Settings.Default.DigitalSignLocation;
            appearance.Contact = Properties.Settings.Default.DigitalSignContact;
            if (Properties.Settings.Default.DigitalSignAppearance == 1)
            {
                appearance.SetVisibleSignature(new iTextSharp.text.Rectangle(20, 10, 170, 60), 1, "Signed");
            }
            appearance.SignatureRenderingMode = PdfSignatureAppearance.RenderingMode.DESCRIPTION;
            MakeSignature.SignDetached(appearance, externalSignature, chain, null, null, null, 0, CryptoStandard.CMS);
            //MakeSignature.SignDetached(signatureAppearance, externalSignature, chain, null, null, null, 0, CryptoStandard.CADES);
        }catch(Exception e){
            Console.WriteLine(e.Message, 1);
            File.Delete(outPdfFile);
        }
        finally
        {
            if (reader != null)
                reader.Close();
            if (stamper != null)
                stamper.Close();
            if (os != null)
                os.Close();                
        }
    }

推荐答案

根据您的屏幕快照，您需要一种特殊的签名，即认证签名.您可以通过添加

According to your screen shot you want a special kind of signature, a certification signature. You can create such a signature by adding

appearance.CertificationLevel = PdfSignatureAppearance.CERTIFIED_FORM_FILLING_AND_ANNOTATIONS;

您的代码.另外，要允许较少的更改，请使用CERTIFIED_FORM_FILLING或CERTIFIED_NO_CHANGES_ALLOWED.

to your code. Alternatively, to allow less changes, use CERTIFIED_FORM_FILLING or CERTIFIED_NO_CHANGES_ALLOWED.

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