Password protecting a PDF file

Question

I have the following:

routine X that creates a PDF file on a daily basis.
routine Y that attaches this file to an Outlook e-mail and sends it to recipients.

Both the above are in VBA. They are called from a C# console application.

Once the PDF has been created I need to password protect it. To do this via VBA without purchasing third party software is quite involved.

What is the simplest solution using C#?

(I'm suspecting there will be an inverse relationship between amount we spend and complexity of answer!)

If you only need to password protect your pdf file then use http://itextpdf.com/ library. For more info goto this: http://stackoverflow.com/questions/370571/password-protected-pdf-using-c-sharp — , Sep 12 '12 at 07:56
@DanielHilgarth two people have voted to close this question - I've tried to be very specific; are there any possible edits I can make to make it more acceptable? — whytheq, Sep 12 '12 at 08:17
@whytheq: I was one of the persons voting to close the question. My reason was that there wasn't a concrete problem. You asked for general guidance. I never did PDF editing - my answer is the result of five minutes of googling. You could have done this yourself. — Daniel Hilgarth, Sep 12 '12 at 08:25
@DanielHilgarth I think a lot of people use SO for a first port of call so to keep this question open isn't a bad thing as your answer is good and concise i.e Google can be avoided. Although I suspect I'll have more code specific questions when implementing your answer so the code will still end up on here. Thanks for the help. — whytheq, Sep 12 '12 at 08:40
@whytheq: No need to avoid google - it can be used to find answers faster than using SO. — Daniel Hilgarth, Sep 12 '12 at 08:43
@DanielHilgarth I use Google all the time; I also get the feeling SO is turning into a massive stand alone resource. — whytheq, Sep 12 '12 at 08:45
@whytheq: Indeed, it is. A lot of my google searches end up here :-) — Daniel Hilgarth, Sep 12 '12 at 08:51
@DanielHilgarth Q.E.D ...pass go on Google and come straight to SO — whytheq, Sep 12 '12 at 16:59

score 29 · Accepted Answer · answered Sep 12 '12 at 07:57

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PDFSharp should be able to protect a PDF file with a password:

// Open an existing document. Providing an unrequired password is ignored.
PdfDocument document = PdfReader.Open(filename, "some text");

PdfSecuritySettings securitySettings = document.SecuritySettings;

// Setting one of the passwords automatically sets the security level to 
// PdfDocumentSecurityLevel.Encrypted128Bit.
securitySettings.UserPassword  = "user";
securitySettings.OwnerPassword = "owner";

// Don't use 40 bit encryption unless needed for compatibility reasons
//securitySettings.DocumentSecurityLevel = PdfDocumentSecurityLevel.Encrypted40Bit;

// Restrict some rights.
securitySettings.PermitAccessibilityExtractContent = false;
securitySettings.PermitAnnotations = false;
securitySettings.PermitAssembleDocument = false;
securitySettings.PermitExtractContent = false;
securitySettings.PermitFormsFill = true;
securitySettings.PermitFullQualityPrint = false;
securitySettings.PermitModifyDocument = true;
securitySettings.PermitPrint = false;

// Save the document...
document.Save(filename);

Reference:
http://www.pdfsharp.net/wiki/ProtectDocument-sample.ashx

answered Sep 12 '12 at 07:57

Daniel Hilgarth

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this looks good & relatively simple - is it totally open source? i.e even for commercial use it is free? – whytheq Sep 12 '12 at 08:15
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@whytheq: [Yes](http://www.pdfsharp.net/Licensing.ashx), it is free to use even in commercial products. – Daniel Hilgarth Sep 12 '12 at 08:16
had a play this afternoon - excellent; I've imported all the source code folders...even had a little nose through the source code! – whytheq Sep 12 '12 at 16:59
@whytheq: Cool :-) I want to point out that it would have been enough to reference the compiled assembly from your code. – Daniel Hilgarth Sep 12 '12 at 17:03
ok added this subsequent [SO question](http://stackoverflow.com/questions/12391244/pdfsharp-getting-started) and the PdfSharp team answered; they seem to favour importing all the folders. I think they mentioned that it adds intellisense. For me, as a c# newbie, i enjoyed adding the projects as it gave me a sense of what is actually being used when I put `using x` at the top of a code module; a reference seems a little more black-box. – whytheq Sep 20 '12 at 11:16
@whytheq: You can have intellisense without adding the project. Simply place the pdfsharp.dll.xml file beside the pdfsharp.dll. – Daniel Hilgarth Sep 20 '12 at 11:25
thanks - not sure of the reason then why the pdfsharp team suggest importing the projects. When I add a reference using VS what does it do? - just physically move a copy of the `.dll` file into the project/solution? ...I could effectively just use import existsing item and go and find the dll and bring it into the project; would be equivalent to using the references? Or is adding a reference just a pointer to somewhere else on my machine? – whytheq Sep 20 '12 at 13:57
@whytheq: Maybe you should ask that as a new question. It seems like you are missing some basics here :-) Others are better at explaining basics than I am... – Daniel Hilgarth Sep 20 '12 at 14:30
hmmm - I am still learning the basics. basic questions can sometimes be hounded out of SO - I might be better Googling. thanks for all the help on this question. – whytheq Sep 20 '12 at 14:43
@DanielHilgarth can this document be opened in PdfSharp after password protection is applied..? if not, how we are gonna load this document again..? – shashwat May 13 '13 at 13:07
@harsh: It should be supported. The sample I posted already hints at it: *// Open an existing document. **Providing an unrequired password is ignored**.* – Daniel Hilgarth May 13 '13 at 13:08
@DanielHilgarth- So is there a way we can make password a required thing to open the document..? – shashwat May 13 '13 at 13:12
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@harsh: Yes, sure. Not clear what you are asking here or what your problem is. My answer shows how to password protect a PDF file. The second parameter to `PdfReader.Open` is the passwort needed to open a password protected PDF file. If you have any further questions, please post them as such if they haven't been answered already: http://stackoverflow.com/questions/ask – Daniel Hilgarth May 13 '13 at 13:14

Hakan Fıstık · Answer 2 · 2023-03-13T12:24:35.810

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For .NET Core/.NET 5 and up only

PdfSharp works only on old .NET Framework.
PdfSharpCore is the same library just ported to the new .NET (.NET Core).

The above answer by @Daniel Hilgarth still works without any change to the code with the ported library.

NOTE This library is under MIT LICENSE, so nothing to worry about.

edited Mar 13 '23 at 12:24

answered Jan 23 '23 at 11:08

Hakan Fıstık

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Password protecting a PDF file

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