C# – checking if pdf is password protected using itextsharp

citextsharpnetpdf

I want to check if a pdf file is password protected or not to view. That is i want to know if the pdf file has user password or not.

I found some help in some forum about it to use isencrypted function but it does not give correct answer.

Is it possible to check if a pdf is password protected?

Best Answer

The problem with using the PdfReader.IsEncrypted method is that if you attempt to instantiate a PdfReader on a PDF that requires a password - and you don't supply that password - you'll get a BadPasswordException.

Keeping this in mind you can write a method like this:

public static bool IsPasswordProtected(string pdfFullname) {
    try {
        PdfReader pdfReader = new PdfReader(pdfFullname);
        return false;
    } catch (BadPasswordException) {
        return true;
    }
}

Note that if you supply an invalid password you'll get the same BadPasswordException when attempting to construct a PdfReader object. You can use this to create a method that validates a PDF's password:

public static bool IsPasswordValid(string pdfFullname, byte[] password) {
    try {
        PdfReader pdfReader = new PdfReader(pdfFullname, password);
        return false;
    } catch (BadPasswordException) {
        return true;
    }
}

Sure it's ugly but as far as I know this is the only way to check if a PDF is password protected. Hopefully someone will suggest a better solution.

Related Solutions

C# – Should ‘using’ directives be inside or outside the namespace

There is actually a (subtle) difference between the two. Imagine you have the following code in File1.cs:

// File1.cs
using System;
namespace Outer.Inner
{
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now imagine that someone adds another file (File2.cs) to the project that looks like this:

// File2.cs
namespace Outer
{
    class Math
    {
    }
}

The compiler searches Outer before looking at those using directives outside the namespace, so it finds Outer.Math instead of System.Math. Unfortunately (or perhaps fortunately?), Outer.Math has no PI member, so File1 is now broken.

This changes if you put the using inside your namespace declaration, as follows:

// File1b.cs
namespace Outer.Inner
{
    using System;
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now the compiler searches System before searching Outer, finds System.Math, and all is well.

Some would argue that Math might be a bad name for a user-defined class, since there's already one in System; the point here is just that there is a difference, and it affects the maintainability of your code.

It's also interesting to note what happens if Foo is in namespace Outer, rather than Outer.Inner. In that case, adding Outer.Math in File2 breaks File1 regardless of where the using goes. This implies that the compiler searches the innermost enclosing namespace before it looks at any using directive.

Html – Recommended way to embed PDF in HTML

This is quick, easy, to the point and doesn't require any third-party script:

<embed src="http://example.com/the.pdf" width="500" height="375" 
 type="application/pdf">

UPDATE (2/3/2021)

Adobe now offers it's own PDF Embed API.

https://www.adobe.io/apis/documentcloud/dcsdk/pdf-embed.html

UPDATE (1/2018):

The Chrome browser on Android no longer supports PDF embeds. You can get around this by using the Google Drive PDF viewer

<embed src="https://drive.google.com/viewerng/
viewer?embedded=true&url=http://example.com/the.pdf" width="500" height="375">

Best Answer

Related Solutions

C# – Should ‘using’ directives be inside or outside the namespace

Html – Recommended way to embed PDF in HTML

Related Topic