使用Itextsharp为PDF添加时间戳

时间:2018-04-30 11:36:04

标签: c# pdf timestamp itext digital-signature

在使用Itextsharp和MakeSignature.SignDetached方法为PDF文件加时间戳时遇到问题。

  • 我的证书存储在Luna HSM上。
  • itextsharp ver:5.5.11
  • PkcsInterop.PDF ver:1.3.0

没有时间戳,下面的代码工作正常。当我想用时间戳签名时抛出异常:

  

远程服务器返回错误:(504)网关超时。

Fiddler给了我那个回复标题:

  

HTTP / 1.1 504 Fiddler - 收到失败日期:星期一,2018年4月30日11:28:57   GMT内容类型:text / html; charset = UTF-8连接:关闭   缓存控制:无缓存,必须重新验证时间戳:14:28:57.430   [Fiddler] ReadResponse()失败:服务器未返回完整   响应此请求。服务器返回0字节

        public void SignPDF(byte[] pdf, SignData signData) //signData: my custom class, it's about sign image,location,size
    {
        string timeStampServer = "http://xxxxxxxx";
        string timeStampUser = "xxxx";
        string timeStampPass = "xxxx";

        string cryptokiDLL = @"C:\Program Files\SafeNet\LunaClient\cryptoki.dll";
        string tokenLabel = "xxx";
        string pin = "xxxx";
        string primaryKeyLabel = "xxxxx";
        string certsDir = @"C:\CERTs";

        iTextSharp.text.Image signImg = null;
        iTextSharp.text.Rectangle signRec = null;
        byte[] signedPDF = null;
        string hash = null;

        try
        {

            HashAlgorithm hashAlgorithm = HashAlgorithm.SHA256;
            Pkcs11RsaSignature pkcs11RsaSignature = new Pkcs11RsaSignature(cryptokiDLL, null, tokenLabel, pin, primaryKeyLabel, null, hashAlgorithm);
            byte[] signingCertificate = pkcs11RsaSignature.GetSigningCertificate();//1460 
            List<byte[]> otherCertificates = new List<byte[]>();
            foreach (string file in Directory.GetFiles(certsDir))
                otherCertificates.Add(File.ReadAllBytes(file));
            var chain = CertUtils.BuildCertPath(signingCertificate, otherCertificates).ToList();

            ITSAClient tsaClient = new TSAClientBouncyCastle(timeStampServer, timeStampUser, timeStampPass);

            IOcspClient ocspClient = new OcspClientBouncyCastle();

            List<ICrlClient> crlList = new List<ICrlClient>();
            crlList.Add(new CrlClientOnline(chain));

            using (PdfReader pdfReader = new PdfReader(pdf))
            {
                using (MemoryStream msPDFfinal = new MemoryStream())
                {
                    using (PdfStamper pdfStamper = PdfStamper.CreateSignature(pdfReader, msPDFfinal, '\0'))
                    {
                        PdfWriter writer = pdfStamper.Writer;
                        PdfSignatureAppearance appearance = pdfStamper.SignatureAppearance;

                        byte[] signImgBinary = signData.ImzaBinary;
                        int x = signData.X;
                        int y = signData.Y;
                        int scale = signData.Scale;
                        int pageNum = signData.PageNum;

                        signImg = iTextSharp.text.Image.GetInstance(signImgBinary);
                        signImg.ScalePercent(scale);

                        float imgX = (float)x;
                        float imgY = (float)y;
                        float scaledW = signImg.ScaledWidth;
                        float scaledH = signImg.ScaledHeight;

                        signRec = new iTextSharp.text.Rectangle(imgX, imgY, imgX + scaledW, imgY + scaledH);

                        appearance.Layer2Text = " ";
                        appearance.Image = signImg;
                        appearance.SetVisibleSignature(signRec, pageNum, "SIG");

                        //without timestamp, it is signing the pdf. Everything is ok.
                        //MakeSignature.SignDetached(appearance, pkcs11RsaSignature, chain, null, null, null, 0, CryptoStandard.CADES);

                        //it returns 504 error, no server response
                        MakeSignature.SignDetached(appearance, pkcs11RsaSignature, chain, crlList, ocspClient, tsaClient, 0, CryptoStandard.CADES);
                    }

                    signedPDF = msPDFfinal.ToArray();
                }
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

最后,根据这个链接 what is wrong with godaddy's timestamp server and itextsharp? 我添加了用户代理和http协议标头但没有任何更改,仍然收到错误。

 protected internal virtual byte[] GetTSAResponse(byte[] requestBytes) {
            HttpWebRequest con = (HttpWebRequest)WebRequest.Create(tsaURL);
            con.UserAgent = "itextsharp";
            con.ProtocolVersion = HttpVersion.Version10;
            con.ContentLength = requestBytes.Length;
            con.ContentType = "application/timestamp-query";
            con.Method = "POST";
            con.KeepAlive = true;
            if ((tsaUsername != null) && !tsaUsername.Equals("") ) {
                string authInfo = tsaUsername + ":" + tsaPassword;
                authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo), Base64FormattingOptions.None);
                con.Headers["Authorization"] = "Basic " + authInfo;
            }
            Stream outp = con.GetRequestStream();
            outp.Write(requestBytes, 0, requestBytes.Length);
            outp.Close();

0 个答案:

没有答案