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C# PDF Password Library
How to create, generate, open, remove owner password from protected PDF file using C# .net


Help C# Developers to Improve the Security of Your PDF Document by Setting Password in C# .NET Application



ON THIS PAGE:



In this C# tutorial, you learn how to create, update, remove passowrd on a protected PDF file in your .NET WinForms, WPF, ASP.NET applications.

  • Create, add a new password to PDF
  • Update, remove password from PDF file
  • Verify PDF password protected or not
  • Encrypt PDF using RC4, AES
  • Use Unicode in password

How to manage a password protected PDF file using C#

  1. Download XDoc.PDF password manager C# library
  2. Install C# library to add, create, remove PDF password
  3. Step by Step Tutorial












  • Best .NET PDF document manipulation SDK library for PDF document protecting in Visual C# .NET framework project
  • Support .NET WinForms, ASP.NET MVC in IIS, ASP.NET Ajax, Azure cloud service, DNN (DotNetNuke), SharePoint
  • A professional PDF encryption and decryption control able to be integrated in C#.NET WinForm and ASP.NET WebForm application
  • Able to perform PDF file password adding, deleting and changing in Visual Studio .NET project use C# source code in .NET class
  • Allow to decrypt PDF password and open a password protected document in C#.NET framework
  • Support to add password to PDF document online or in C#.NET WinForms for PDF file protection
  • Able to create a password protected PDF contains file permission limitation
  • An advanced PDF password remover component can help users unlock PDF file without password
  • Able to change password on adobe PDF document in C#.NET


To help protect your PDF document in C# project, XDoc.PDF provides some PDF security settings. On this page, we will talk about how to achieve this via password. In general, you can do following manipulations.







How to open a password protected PDF file using C#


The following contents and C# example source code will show how to read, open a password protected PDF file in C# code.

  1. Create a new PDFDocument with an existing PDF file loaded with password provided
  2. Call PDFDocument.Save() to save the PDF file to a new location without password protected


String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String userPassword = @"you";
//  open an encrypted document
PDFDocument doc = PDFDocument.Open(intputFilePath, userPassword);

String outputFilePath = Program.RootPath + "\\" + "Output.pdf";
//  remove the password
doc.Save(outputFilePath);




Add password to a PDF file using C#


The following C# source code will add a password to an existing PDF file (without password protected), and save to a new location. 



String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String outputFilePath = Program.RootPath + "\\" + "1_with_pw.pdf";
String userPassword = "you";
String ownerPassword = "me";
//  create password setting
PasswordSetting setting = new PasswordSetting(userPassword, ownerPassword);
//  add password to plain file
int errorCode = PDFDocument.AddPassword(intputFilePath, outputFilePath, setting);
if (errorCode == 0)
{
    Console.WriteLine("Success");
}
else
{
    Console.WriteLine("Failed");
}


The following C# source code will add a password to PDF file. 



String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String userPassword = "you";
String ownerPassword = "me";
//  create password setting
PasswordSetting setting = new PasswordSetting(userPassword, ownerPassword);
//  add password to plain file
int errorCode = PDFDocument.AddPassword(intputFilePath, setting);
if (errorCode == 0)
{
    Console.WriteLine("Success");
}
else
{
    Console.WriteLine("Failed");
}


Add password to a PDF in stream object or byte arrary using c#


The following C# source code will add a password to PDF in Stream object and save to a new Stream object. 



String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String outputFilePath = Program.RootPath + "\\" + "1_with_pw.pdf";

FileStream inputStream = File.Open(intputFilePath, FileMode.Open, FileAccess.Read);
FileStream outputStream = File.Open(intputFilePath, FileMode.Create, FileAccess.ReadWrite);
String userPassword = "you";
String ownerPassword = "me";
//  create password setting
PasswordSetting setting = new PasswordSetting(userPassword, ownerPassword);
//  add password to a plain file stream
int errorCode = PDFDocument.AddPassword(inputStream, outputStream, setting);
if (errorCode == 0)
{
    Console.WriteLine("Success");
}
else
{
    Console.WriteLine("Failed");
}




Update password on a protected PDF file using c#


Output to a new file 



String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String outputFilePath = Program.RootPath + "\\" + "1_with_pw.pdf";
String userPassword = "you";
String newUserPassword = "fill";
String newOwnerPassword = "watch";
//  create setting for the new password
PasswordSetting setting = new PasswordSetting(newUserPassword, newOwnerPassword);
//  change password for an encrypted file
int errorCode = PDFDocument.ChangePassword(intputFilePath, outputFilePath, userPassword, setting);
if (errorCode == 0)
{
    Console.WriteLine("Success");
}
else
{
    Console.WriteLine("Failed");
}


Overwrite the original file 



String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String userPassword = "you";
String newUserPassword = "fill";
String newOwnerPassword = "watch";
//  create setting for the new password
PasswordSetting setting = new PasswordSetting(newUserPassword, newOwnerPassword);
//  change password for an encrypted file
int errorCode = PDFDocument.ChangePassword(intputFilePath, userPassword, setting);
if (errorCode == 0)
{
    Console.WriteLine("Success");
}
else
{
    Console.WriteLine("Failed");
}




Change password on PDF in stream object or byte array using c#


String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String outputFilePath = Program.RootPath + "\\" + "1_with_pw.pdf";

FileStream inputStream = File.Open(intputFilePath, FileMode.Open, FileAccess.Read);
FileStream outputStream = File.Open(intputFilePath, FileMode.Create, FileAccess.ReadWrite);
String userPassword = "you";
String newUserPassword = "fill";
String newOwnerPassword = "watch";
//  create setting for the new password
PasswordSetting setting = new PasswordSetting(newUserPassword, newOwnerPassword);
//  change password for an encrypted file
int errorCode = PDFDocument.ChangePassword(inputStream, outputStream, userPassword, setting);
if (errorCode == 0)
{
    Console.WriteLine("Success");
}
else
{
    Console.WriteLine("Failed");
}




Remove the password from a protected PDF file using C#


Output to a new file 



String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String userPassword = @"you";
String outputFilePath = Program.RootPath + "\\" + "Remove.pdf";
//  remove password in the input file and output to a new file
int errorCode = PDFDocument.RemovePassword(intputFilePath, outputFilePath, userPassword);
if (errorCode == 0) Console.WriteLine("Success");
else Console.WriteLine("Failed");


Overwrite the original file 



String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String userPassword = @"you";
//  remove password in the file
int errorCode = PDFDocument.RemovePassword(intputFilePath, userPassword);
if (errorCode == 0) Console.WriteLine("Success");
else Console.WriteLine("Failed");




Remove the password from PDF in stream object or byte array using c#


String intputFilePath = Program.RootPath + "\\" + "1.pdf";
String outputFilePath = Program.RootPath + "\\" + "Remove.pdf";

FileStream inputStream = File.Open(intputFilePath, FileMode.Open, FileAccess.Read);
FileStream outputStream = File.Open(intputFilePath, FileMode.Create, FileAccess.ReadWrite);
String userPassword = @"you";

int errorCode = PDFDocument.RemovePassword(inputStream, outputStream, userPassword);
if (errorCode == 0)
{
    Console.WriteLine("Success");
}
else
{
    Console.WriteLine("Failed");
}






How to verify if a PDF file is password protected or not using c#


Remarks: If a PDF file does not been encrypted, it should never have any password. 



String intputFilePath = Program.RootPath + "\\" + "1.pdf";

bool isEncrypted = PDFDocument.IsEncrypted(intputFilePath);
bool hasUserPassword = PDFDocument.HasUserPassword(intputFilePath);

Console.WriteLine(@"This file is encrypted: " + isEncrypted);
Console.WriteLine(@"Password is not empty: " + hasUserPassword);






PDF passsword more encryption methods in C#


The C# source code below shows how to encrypt a PDF using

  • RC4 with 40-bit key
  • RC4 with 128-bit key
  • AES with 128-bit key
  • AES with 256-bit key



String inputFilePath = @"C:\1.pdf";
String outputFolder = @"C:\";

String userPassword = "1234";
String ownerPassword = "5678";

//  Encrypt file by using RC4 with 40-bit key
PasswordSetting settings1 = new PasswordSetting(userPassword, ownerPassword);
settings1.Level = EncryptionLevel.RC4_40bit;
PDFDocument.AddPassword(inputFilePath, outputFolder + "1.rc4_40.pdf", settings1);

//  Encrypt file by using RC4 with 128-bit key
PasswordSetting settings2 = new PasswordSetting(userPassword, ownerPassword);
settings2.Level = EncryptionLevel.RC4_128bit;
PDFDocument.AddPassword(inputFilePath, outputFolder + "1.rc4_128.pdf", settings2);

//  Encrypt file by using AES with 128-bit key
PasswordSetting settings3 = new PasswordSetting(userPassword, ownerPassword);
settings3.Level = EncryptionLevel.AES_128bit;
PDFDocument.AddPassword(inputFilePath, outputFolder + "1.aes_128.pdf", settings3);

//  Encrypt file by using AES with 256-bit key
PasswordSetting settings4 = new PasswordSetting(userPassword, ownerPassword);
settings4.Level = EncryptionLevel.AES_256bit;
PDFDocument.AddPassword(inputFilePath, outputFolder + "1.aes_256.pdf", settings4);






How to add password using Unicode to PDF file in C#.NET


The following C# source code will show how to add a new password using Unicode (Chinese characters) to a PDF file using C#.

To encode Unicode in PDF password, you need encrypt PDF file using AES with 256-bit key. 



String inputFilePath = Program.RootPath + "\\" + "1.pdf";
String outputFolder = Program.RootPath + "\\";

String userPassword = "用户密码";
String ownerPassword = "拥有者密码";

//  Encrypt file by using AES with 256-bit key
//  Note:
//  Only AES-256 support Unicode in passwords
PasswordSetting settings = new PasswordSetting(userPassword, ownerPassword);
settings.Level = EncryptionLevel.AES_256bit;
PDFDocument.AddPassword(inputFilePath, outputFolder + "1.aes_256.pdf", settings);