C# iTextSharp由字段签名

我（终于）能够用我的签名制作一个签名的PDF，但我一生都无法计算“签名人”字段。只有3个字段，联系人、原因、位置。其他字段为日期和签名人。我不确定日期是如何填写的。您可以看到，我尝试了几个明显的签名者字段，但没有soap

我在写我的代码，以防它对其他人有帮助……我花了一段时间才弄明白这一点

static private void SignIt()
{
    // Creating the reader and the stamper
    PdfReader reader = null;
    PdfStamper stamper = null;
    FileStream os = null;

    try
    {
        string sigFileName = "c:\\temp\\signature.jpg";
        string inputFile = "C:\\temp\\mypdf.pdf";
        string outputFile = "C:\\temp\\mypdfsigned.pdf";
        string certFileName = "c:\\temp\\adcl.pfx";
        string certPassword = "adcl214";
        StringBuilder sb = new StringBuilder();
        PdfReader myReader = new PdfReader(inputFile);

        reader = new PdfReader(inputFile);
        os = new FileStream(outputFile, FileMode.Create);

        //Activate MultiSignatures
        stamper = PdfStamper.CreateSignature(reader, os, '\0', null, true);

        //To disable Multi signatures uncomment this line : every new signature will invalidate older ones !
        //stamper = PdfStamper.CreateSignature(reader, os, '\0');


        // Creating the appearance
        PdfSignatureAppearance appearance = stamper.SignatureAppearance;
        Rectangle rectangle = new Rectangle(275, 25, 500, 100);
        appearance.SetVisibleSignature(rectangle, 1, "Revision " + 1 + "|" + 1);

        appearance.SignatureCreator = "Robert Dejournett, PhD";
        appearance.Reason = "Signed";
        appearance.Location = "MD Anderson Cancer Center";
        appearance.Contact = "Robert Dejournett";
        appearance.Layer2Text = "Signed on " + DateTime.Now;

        appearance.SignatureRenderingMode = iTextSharp.text.pdf.PdfSignatureAppearance.RenderingMode.DESCRIPTION;
        PdfTemplate n2 = appearance.GetLayer(2);
        n2.AddImage(AddSignatureImage(sigFileName));

        // generate cert file
        if (!System.IO.File.Exists(certFileName)) GenerateCertToFile(certFileName, certPassword);


        // do needful to get cert info
        Pkcs12Store store = new Pkcs12Store(new FileStream(certFileName, FileMode.Open), certPassword.ToCharArray());

        ICollection<Org.BouncyCastle.X509.X509Certificate> chain = new List<Org.BouncyCastle.X509.X509Certificate>();
        String alias = "";
        foreach (string al in store.Aliases)
            if (store.IsKeyEntry(al) && store.GetKey(al).Key.IsPrivate)
            {
                alias = al;
                break;
            }
        AsymmetricKeyEntry pk = store.GetKey(alias);
        foreach (X509CertificateEntry c in store.GetCertificateChain(alias))
            chain.Add(c.Certificate);

        RsaPrivateCrtKeyParameters parameters = pk.Key as RsaPrivateCrtKeyParameters;

        IExternalSignature pks = new PrivateKeySignature(parameters, DigestAlgorithms.SHA256);
        pks.Sign(Encoding.ASCII.GetBytes("Robert Dejournett"));

        MakeSignature.SignDetached(appearance, pks, chain, null, null, null, 0, CryptoStandard.CMS);

        stamper.Close();
    }

    catch (Exception ex)
    {
        Console.WriteLine("GMA: " + ex.Message);
    }
    finally
    {
        if (reader != null)
            reader.Close();
        if (stamper != null)
            stamper.Close();
        if (os != null)
            os.Close();
    }
}

编辑-这就是我的意思

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尝试将证书添加到受信任的证书列表应能解决此问题

我对受信任站点颁发的证书没有问题，但如果证书来源未知，则会发生此问题。

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最后，我使用您的代码创建了一个应用程序，并在将证书添加到可信站点后自动解决了这个问题。

您无法看到签名图像吗？@Rex否，图像正常。联系人、位置等附近有一个未填充的“签名人”字段。我不知道如何填充该字段。看到新的屏幕截图。你能分享有问题的PDF吗？谢谢，这样你就可以在GenerateCertToFile中看到上面生成证书的代码-我想在“签名人”中显示的文本放在哪里。我查看了X509V3CertificateGenerator对象，没有看到明显的斑点。我正在填充SubjectDN和IssuerDN，在“signed by”上我看不到它们。我也按照您的建议将证书导入到证书存储中（这并没有解决问题）。我没有修改您的代码并向我显示由“mdanderson.org”签名的证书，该证书是SubjectDN（但由于证书不是受信任的证书，所以没有第一次显示）。稍后，将通过代码生成的证书添加到受信任的证书，然后重新打开生成的PDF解决了我的问题。我已在此处上载了我的解决方案，我使用的是Acrobat reader Dc 2017版本。在Acrobat reader->中从签名属性-->显示签名者的证书->信任选项卡->添加到中打开PDF可信证书。我们需要这样做的原因是为了信任站点，因为证书是在运行时生成的，这是未知的。我尝试在Acrobat和Nitro中打开相同的PDF，但Acrobat shows的签名是where as Nitro，而不是

static private void GenerateCertToFile(string certFileName, string password)
{
    RsaKeyPairGenerator kpGenerator = new RsaKeyPairGenerator();
    kpGenerator.Init(new KeyGenerationParameters(new SecureRandom(), 2048));
    // Create a keypair
    AsymmetricCipherKeyPair kp = kpGenerator.GenerateKeyPair();
    // Certificate Generator
    X509V3CertificateGenerator cGenerator = new X509V3CertificateGenerator();
    cGenerator.SetSerialNumber(BigInteger.ProbablePrime(120, new Random()));
    cGenerator.SetSubjectDN(new X509Name("CN=" + "mdanderson.org"));
    cGenerator.SetIssuerDN(new X509Name("CN=" + "ADCL"));
    cGenerator.SetNotBefore(DateTime.Now);
    cGenerator.SetNotAfter(DateTime.Now.Add(new TimeSpan(365, 0, 0, 0))); // Expire in 1 year
    //cGenerator.SetSignatureAlgorithm(HashType.SHA1withDSA.ToString()); // See the Appendix Below for info on the hash types supported by Bouncy Castle C#
    cGenerator.SetSignatureAlgorithm("SHA256WithRSA");

    cGenerator.SetPublicKey(kp.Public); // Only the public key should be used here!
    Org.BouncyCastle.X509.X509Certificate cert = cGenerator.Generate(kp.Private); // Create a self-signed cert

    // Create the PKCS12 store
    Pkcs12Store store = new Pkcs12StoreBuilder().Build();
    // Add a Certificate entry
    X509CertificateEntry certEntry = new X509CertificateEntry(cert);
    store.SetCertificateEntry(cert.SubjectDN.ToString(), certEntry); // use DN as the Alias.
                                                                     // Add a key entry
    AsymmetricKeyEntry keyEntry = new AsymmetricKeyEntry(kp.Private);
    store.SetKeyEntry(cert.SubjectDN.ToString() + "_key", keyEntry, new X509CertificateEntry[] { certEntry }); // Note that we only have 1 cert in the 'chain'

    // Save to the file system
    using (var filestream = new FileStream(certFileName, FileMode.Create, FileAccess.ReadWrite))
    {
        store.Save(filestream, password.ToCharArray(), new SecureRandom());
    }
}