Hi there I´m new to iTextSharp and I´m testing the examples in the site. (The
code can be finded here
http://itextpdf.sourceforge.net/howtosign.html#signextitextsharp2). Right now
I'm trying to sign a PDF with a Smart Card certificate. I used this code that
it's available on line, as a sample code but I can't make it work. public
static void SignHashed() {
X509Certificate2 card = GetCertificate();
Org.BouncyCastle.X509.X509CertificateParser cp = new
Org.BouncyCastle.X509.X509CertificateParser();
Org.BouncyCastle.X509.X509Certificate[] chain = new
Org.BouncyCastle.X509.X509Certificate[]{cp.ReadCertificate(card.RawData)};
PdfReader reader = new PdfReader("c:\\hello.pdf");
PdfStamper stp = PdfStamper.CreateSignature(reader, new
FileStream("c:\\hello_hashed.pdf", FileMode.Create), '\0');
PdfSignatureAppearance sap = stp.SignatureAppearance;
sap.SetVisibleSignature(new Rectangle(100, 100, 300, 200), 1, null);
sap.SignDate = DateTime.Now;
sap.SetCrypto(null, chain, null, null);
sap.Reason = "I like to sign";
sap.Location = "Universe";
sap.Acro6Layers = true;
sap.Render = PdfSignatureAppearance.SignatureRender.NameAndDescription;
PdfSignature dic = new PdfSignature(PdfName.ADOBE_PPKMS,
PdfName.ADBE_PKCS7_SHA1);
dic.Date = new PdfDate(sap.SignDate);
dic.Name = PdfPKCS7.GetSubjectFields(chain[0]).GetField("CN");
if (sap.Reason != null)
dic.Reason = sap.Reason;
if (sap.Location != null)
dic.Location = sap.Location;
sap.CryptoDictionary = dic;
int csize = 4000;
Dictionary<PdfName,int> exc = new Dictionary<PdfName,int>();
exc[PdfName.CONTENTS] = csize * 2 + 2;
sap.PreClose(exc); //this is the line where the code fails
HashAlgorithm sha = new SHA1CryptoServiceProvider();
Stream s = sap.GetRangeStream();
int read = 0;
byte[] buff = new byte[8192];
while ((read = s.Read(buff, 0, 8192)) > 0) {
sha.TransformBlock(buff, 0, read, buff, 0);
}
sha.TransformFinalBlock(buff, 0, 0);
byte[] pk = SignMsg(sha.Hash, card, false);
byte[] outc = new byte[csize];
PdfDictionary dic2 = new PdfDictionary();
Array.Copy(pk, 0, outc, 0, pk.Length);
dic2.Put(PdfName.CONTENTS, new PdfString(outc).SetHexWriting(true));
sap.Close(dic2);
}The error is thisSystem.NullReferenceException was unhandled
Message=Object reference not set to an instance of an object.
Source=itextsharp
StackTrace:
at
iTextSharp.text.pdf.security.CertificateInfo.GetSubjectFields(X509Certificate
cert)
at iTextSharp.text.pdf.PdfSignatureAppearance.GetAppearance()
at iTextSharp.text.pdf.PdfSignatureAppearance.PreClose(Dictionary`2
exclusionSizes)
at FirmaDocs.Form1.SignHashed() in H:\...\Form1.cs:line 217
at FirmaDocs.Form1.button1_Click(Object sender, EventArgs e) in
H:\...\Form1.cs:line 186
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons
button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd,
Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at
System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr
dwComponentID, Int32 reason, Int32 pvLoopData)
at
System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32
reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32
reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at FirmaDocs.Program.Main() in H:\...\Program.cs:line 18
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[]
args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence
assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
Can anyone please help me, this error is driving me crazy.
JMC ------------------------------------------------------------------------------
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