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Validity unknown symbol is not being displayed on PDF

I am using the below c# code (IText7 library) to set the appearance object to show the digital signature on my pdf.
string destPdf = "D:\\UnsignedPDF.pdf";
string srcPdf = "D:\\SignedPDF.pdf";
PdfReader reader = new PdfReader(srcPdf);
PdfSigner signer = new PdfSigner(reader,
new FileStream(destPdf, FileMode.Create),
new StampingProperties());
PdfSignatureAppearance appearance = signer.GetSignatureAppearance();
appearance.SetReason("My reson to sign...")
.SetLocation("India")
.SetPageRect(new Rectangle(36, 648, 200, 100))
.SetPageNumber(1);
signer.SetFieldName("MyFieldName");
A digital signature is printed on my pdf but not as what I expected, it should show a validity unknown symbol or signature valid symbol but it is not getting printed. I am getting it printed like below image.
but my expectation is to print it like below images:

A digital signature is printed on my pdf but not as what I expected, it should show a validity unknown symbol or signature valid symbol but it is not getting printed.
No, it shouldn't.
What you describe is a behavior that has been deprecated in 2003 when Adobe Acrobat 6 has been published. In particular that behavior has never been specified in the ISO PDF specification ISO 32000; on the contrary it has been forbidden in the update ISO 32000-2. For references read this answer.
With respect to iText:
iText(Sharp) 5.x, having inherited its signing API implementation base from iText 2.x/4.x, still offered a backward switch (PdfSignatureAppearance.Acro6Layers) which set to false allowed the creation of signature appearances supporting those in-document validation status marks.
iText 7.x, being a product started in the 2010s, got rid of this burden.
If you happen to work in a context which technologically got stuck in the early 2000s, and if you indeed are required to enable such (nowadays invalid) behavior, you may consider re-integrating the code for generating those pre-Acrobat6 layers in the current iText 7 sign module. If you compare the PdfSignatureAppearance.GetAppearance() source iText 5 and iText 7, you find quickly where with Acro6Layers == false additional layers where added.

How to Check PDF is Reader enabled or not using C#?

My only requirement is to find a selected pdf in a folder is Reader enabled or not, more specifically if usage rights are defined in a way that allows people to add annotations (e.g. comments).
I am doing this in windows application. If I click a button, an event is triggered searching a folder for PDF files. This event needs to check whether or not the PDFs in the folder are Reader enabled for comments. If they are, I need to remove the comment usage rights or revert the PDF back to its original version.
My code can only find PDF files in the folder. I don`t know how to check if the selected PDF is comment enabled or not. Please be gentle and suggest solution.
Here's my code:
private void button1_Click(object sender, EventArgs e)
{
{
string[] filePaths = Directory.GetFiles("D:\\myfolder\\pdffolder");
List<ListViewItem> files = new List<ListViewItem>();
foreach (string filePath in filePaths)
{
---need to check comment enabled or not---
}
}
}

You want to know if a PDF is Reader enabled or not. Reader enabling is established by adding a digital signature known as a Usage Rights (UR) signature. If you have an instance of PdfReader, you can check whether or not a PDF is Reader enabled by using the hasUsageRights() method:
PdfReader reader = new PdfReader(path_to_file);
boolean isReaderEnabled = reader.hasUsageRights();
Usage rights can encompass many different things, such as allowing people to comment, allowing people to save a filled out form, allowing people to sign a document,...
To find out which rights are enabled, you have to inspect either the UR or the UR3 dictionary (note that UR is deprecated, but there may still be PDFs out there that have a UR dictionary):
PdfDictionary catalog = reader.getCatalog();
PdfDictionary perms = catalog.getAsDict(PdfName.PERMS);
PdfDictionary ur = null;
if (perms != null) {
PdfDictionary ur = perms.getAsDict(PdfName.UR);
if (ur == null)
ur = perms.getAsDict(PdfName.UR3);
}
}
If ur remains null, there are no usage rights. If you only want to check if commenting is enabled, you'll have to inspect the entries of the ur dictionary. There will be an /Annots entry with as value an array with values such as Create, Delete, Modify, Copy, Import, Export, Online and SummaryView. FOr the full overview of possible entries, see Table 255 "Entries in the UR transform parameters dictionary" of ISO-32000-1.
You can remove all usage rights like this:
PdfReader reader = new PdfReader(path_to_file);
if (reader.hasUsageRights()) {
reader.removeUsageRights();
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(path_to_new_file));
stamper.close();
}
It is impossible to remove only the usage rights for commenting while preserving other usage rights (if present). Just removing the /Annots entry from the /UR or /UR3 dictionary will break the digital signature that enables usage rights. This digital signature is created with a private key owned by Adobe and no third party tool (other than an Adobe product) is allowed to use that key.
Final note:
all code snippet were written in Java, but iTextSharp has corresponding methods or properties in C#. It shouldn't be a problem to port the snippets to C#.
In many cases, it's sufficient to change a lower case into an upper case:
Java: object.add(something);
C#: object.Add(something);
Or you have to remove the set/get:
Java: object.setSomething(something);
C#: object.Something = something;

Thanks for all who takes effect to my question. I finally found the answer in a similar way by reading the PDF and check for a particular string (particular string presented if Comment enabled on the PDF).
The particular string starts with /Annot ....., First I read the PDF thru System.IO, then store in a string and looking for the particular string, If the searching string available then the PDF is comment enabled else not.

Set BaseUrl of an existing Pdf Document

We're having trouble setting a BaseUrl using iTextSharp. We have used Adobes Implementation for this in the past, but we got some severe performance issues. So we switched to iTextSharp, which is aprox 10 times faster.
Adobe enabled us to set a base url for each document. We really need this in order to deploy our documents on different servers. But we cant seem to find the right code to do this.
This code is what we used with Adobe:
public bool SetBaseUrl(object jso, string baseUrl)
{
try
{
object result = jso.GetType().InvokeMember("baseURL", BindingFlags.SetProperty, null, jso, new Object[] {baseUrl });
return result != null;
}
catch
{
return false;
}
}
A lot of solutions describe how you can insert links in new or empty documents. But our documents already exist and do contain more than just text. We want to overlay specific words with a link that leads to one or more other documents. Therefore, its really important to us that we can insert a link without accessing the text itself. Maybe lay a box ontop of these words and set its position (since we know where the words are located in the document)
We have tried different implementations, using the setAction method, but it doesnt seem to work properly. The result was in most cases, that we saw out box, but there was no link inside or associated with it. (the cursor didn't change and nothing happend, when i clicked inside the box)
Any help is appreciated.

I've made you a couple of examples.
First, let's take a look at BaseURL1. In your comment, you referred to JavaScript, so I created a document to which I added a snippet of document-level JavaScript:
writer.addJavaScript("this.baseURL = \"http://itextpdf.com/\";");
This works perfectly in Adobe Acrobat, but when you try this in Adobe Reader, you get the following error:
NotAllowedError: Security settings prevent access to this property or
method. Doc.baseURL:1:Document-Level:0000000000000000
This is consistent with the JavaScript reference for Acrobat where it is clearly indicated that special permissions are needed to change the base URL.
So instead of following your suggested path, I consulted ISO-32000-1 (which was what I asked you to do, but... I've beaten you in speed).
I discovered that you can add a URI dictionary to the catalog with a Base entry. So I wrote a second example, BaseURL2, where I add this dictionary to the root dictionary of the PDF:
PdfDictionary uri = new PdfDictionary(PdfName.URI);
uri.put(new PdfName("Base"), new PdfString("http://itextpdf.com/"));
writer.getExtraCatalog().put(PdfName.URI, uri);
Now the BaseURL works in both Acrobat and Reader.
Assuming that you want to add a BaseURL to existing documents, I wrote BaseURL3. In this example, we add the same dictionary to the root dictionary of an existing PDF:
PdfReader reader = new PdfReader(src);
PdfDictionary uri = new PdfDictionary(PdfName.URI);
uri.put(new PdfName("Base"), new PdfString("http://itextpdf.com/"));
reader.getCatalog().put(PdfName.URI, uri);
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
stamper.close();
Using this code, you can change a link that points to "index.php" (base_url.pdf) into a link that points to "http://itextpdf.com/index.php" (base_url_3.pdf).
Now you can replace your Adobe license with a less expensive iTextSharp license ;-)

Can a PDF be converted to a vector image format that can be printed from .NET?

We have a .NET app which prints to both real printers and PDF, currently using PDFsharp, although that part can be changed if there's a better option. Most of the output is generated text or images, but there can be one or more pages that get appended to the end. That page(s) are provided by the end-user in PDF format.
When printing to paper, our users use pre-printed paper, but in the case of an exported PDF, we concatenate those pages to the end, since they're already in PDF format.
We want to be able to embed those PDFs directly into the print stream so they don't need pre-printed paper. However, there aren't really any good options for rendering a PDF to a GDI page (System.Drawing.Graphics).
Is there a vector format the PDF could be converted to by some external program, that could rendered to a GDI+ page without being degraded by conversion to a bitmap first?

In an article titled "How To Convert PDF to EMF In .NET," I have shown how to do this using our PDFOne .NET product. EMFs are vector graphics and you can render them on the printer canvas.
A simpler alternative for you is PDF overlay explained in another article titled "PDF Overlay - Stitching PDF Pages Together in .NET." PDFOne allows x-y offsets in overlays that allows you stitch pages on the edges. In the article cited here, I have overlaid the pages one over another by setting the offsets to zero. You will have set it to page width and height.
DISCLAIMER: I work for Gnostice.

Ghostscript can output PostScript (which is a vector file) which can be directly sent to some types of printers. For example, if you're using an LPR capable printer, the PS file can be directly set to that printer using something like this project: http://www.codeproject.com/KB/printing/lpr.aspx
There are also some commercial options which can print a PDF (although I'm not sure if the internal mechanism is vector or bitmap based), for example http://www.tallcomponents.com/pdfcontrols2-features.aspx or http://www.tallcomponents.com/pdfrasterizer3.aspx

I finally figured out that there is an option that addresses my general requirement of embedding a vector format into a print job, but it doesn't work with GDI based printing.
The XPS file format created by Microsoft XPS Writer print driver can be printed from WPF, using the ReachFramework.dll included in .NET. By using WPF for printing instead of GDI, it's possible to embed an XPS document page into a larger print document.
The downside is, WPF printing works quite a bit different, so all the support code that directly uses stuff in the Sytem.Drawing namespace has to be re-written.
Here's the basic outline of how to embed the XPS document:
Open the document:
XpsDocument xpsDoc = new XpsDocument(filename, System.IO.FileAccess.Read);
var document = xpsDoc.GetFixedDocumentSequence().DocumentPaginator;
// pass the document into a custom DocumentPaginator that will decide
// what order to print the pages:
var mypaginator = new myDocumentPaginator(new DocumentPaginator[] { document });
// pass the paginator into PrintDialog.PrintDocument() to do the actual printing:
new PrintDialog().PrintDocument(mypaginator, "printjobname");
Then create a descendant of DocumentPaginator, that will do your actual printing. Override the abstract methods, in particular the GetPage should return DocumentPages in the correct order. Here's my proof of concept code that demonstrates how to append custom content to a list of Xps documents:
public override DocumentPage GetPage(int pageNumber)
{
for (int i = 0; i < children.Count; i++)
{
if (pageNumber >= pageCounts[i])
pageNumber -= pageCounts[i];
else
return FixFixedPage(children[i].GetPage(pageNumber));
}
if (pageNumber < PageCount)
{
DrawingVisual dv = new DrawingVisual();
var dc = dv.Drawing.Append();
dc = dv.RenderOpen();
DoRender(pageNumber, dc); // some method to render stuff to the DrawingContext
dc.Close();
return new DocumentPage(dv);
}
return null;
}
When trying to print to another XPS document, it gives an exception "FixedPage cannot contain another FixedPage", and a post by H.Alipourian demonstrates how to fix it: http://social.msdn.microsoft.com/Forums/da/wpf/thread/841e804b-9130-4476-8709-0d2854c11582
private DocumentPage FixFixedPage(DocumentPage page)
{
if (!(page.Visual is FixedPage))
return page;
// Create a new ContainerVisual as a new parent for page children
var cv = new ContainerVisual();
foreach (var child in ((FixedPage)page.Visual).Children)
{
// Make a shallow clone of the child using reflection
var childClone = (UIElement)child.GetType().GetMethod(
"MemberwiseClone", BindingFlags.Instance | BindingFlags.NonPublic
).Invoke(child, null);
// Setting the parent of the cloned child to the created ContainerVisual
// by using Reflection.
// WARNING: If we use Add and Remove methods on the FixedPage.Children,
// for some reason it will throw an exception concerning event handlers
// after the printing job has finished.
var parentField = childClone.GetType().GetField(
"_parent", BindingFlags.Instance | BindingFlags.NonPublic);
if (parentField != null)
{
parentField.SetValue(childClone, null);
cv.Children.Add(childClone);
}
}
return new DocumentPage(cv, page.Size, page.BleedBox, page.ContentBox);
}
Sorry that it's not exactly compiling code, I just wanted to provide an overview of the pieces of code necessary to make it work to give other people a head start on all the disparate pieces that need to come together to make it work. Trying to create a more generalized solution would be much more complex than the scope of this answer.

While not open source and not .NET native (Delphi based I believe, but offers a precompiled .NET library), Quick PDF can render a PDF to an EMF file which you could load into your Graphics object.

Can I fill in an encrypted PDF with iTextSharp?

I have a fillable, saveable PDF file that has an owner password (that I don't have access to). I can fill it out in Adobe reader, export the FDF file, modify the FDF file, and then import it.
Then I tried to do it with iText for .NET. I can't create a PdfStamper from my PdfReader because I didn't provide the owner password to the reader. Is there any way to do this programmatically or must I recreate the document?
Even using FdfReader requires a PdfStamper. Am I missing anything? Anything legal that is - I'm pretty sure I could hack the document, but I can't. Ironically, recreating it would probably be ok.

This line will bypass edit password checking in iTextSharp:
PdfReader.unethicalreading = true;

[I found this question several months after it was posted and I'm posting this solution now for anyone who comes across this question in a search.]
I was in the exact same situation: my customer had a PDF with fillable fields that I needed to programmatically access. Unfortunately the PDF was password protected and they didn't have the password so I found couldn't work with their file.
What I discovered was that iTextSharp version 4.0.4 (and later) enforces password restrictions, earlier versions did not.
So I downloaded version 4.0.3 and sure enough it worked. In my case I didn't even have to change my code to use this older version.
You can download 4.0.3 (and all other versions) at SourceForge.

Two important things
Set PdfReader.unethicalreading = true to prevent BadPasswordException.
Set append mode in PdfStamper's constructor, otherwise the Adobe Reader Extensions signature becomes broken and Adobe Reader will display following message: "This document contained certain rights to enable special features in Adobe Reader. The document has been changed since it was created and these rights are no longer valid. Please contact the author for the original version of this document."
So all you need to do is this:
PdfReader.unethicalreading = true;
using (var pdfReader = new PdfReader("form.pdf"))
{
using (var outputStream = new FileStream("filled.pdf", FileMode.Create, FileAccess.Write))
{
using (var stamper = new iTextSharp.text.pdf.PdfStamper(pdfReader, outputStream, '\0', true))
{
stamper.AcroFields.Xfa.FillXfaForm("data.xml");
}
}
}
See How to fill XFA form using iText?

Unless someone else chimes in, I'll assume the answer is "No"
I wound up regenerating the PDF in an unencrypted form.