Working with Security

26 Apr 202224 minutes to read

Essential PDF allows you to protect the PDF document using encryption and set permission to the PDF document operations like printing, editing, copy content etc. using user password and owner password. Two types of encryption algorithms are available

Rivest Cipher 4 (RC4)
Advanced Encryption Standard (AES)

Working with RC4 Encryption

You can encrypt PDF document using RC4 algorithm with 40bit or 128bit key size. The following code snippet illustrates how to encrypt the PDF document with the UserPassword.

User password: Prevents people from opening or viewing a PDF document. Once the User Password is set, to open the PDF document, Adobe Acrobat/Reader will prompt a user to enter this password. If it is not correct, the document will not open. By setting a PDF User password, you can secure the PDF document.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key128Bit;

security.Algorithm = PdfEncryptionAlgorithm.RC4;

security.UserPassword = "password";

graphics.DrawString("Encrypted with RC4 128bit", font, brush, new PointF(0, 40));

//Save and close the document.

document.Save("Output.pdf");

document.Close(true);
'Create a new PDF document.

Dim document As New PdfDocument()

Dim page As PdfPage = document.Pages.Add()

Dim graphics As PdfGraphics = page.Graphics

Dim font As New PdfStandardFont(PdfFontFamily.TimesRoman, 20.0F, PdfFontStyle.Bold)

Dim brush As PdfBrush = PdfBrushes.Black

'Document security.

Dim security As PdfSecurity = document.Security

'Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key128Bit

security.Algorithm = PdfEncryptionAlgorithm.RC4

security.UserPassword = "password"

graphics.DrawString("Encrypted with RC4 128bit", font, brush, New PointF(0, 40))

'Save and close the document.

document.Save("Output.pdf")

document.Close(True)
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key128Bit;

security.Algorithm = PdfEncryptionAlgorithm.RC4;

security.UserPassword = "password";

graphics.DrawString("Encrypted with RC4 128bit", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

await document.SaveAsync(stream);

//Close the document

document.Close(true);                                                                   

//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respected code samples

Save(stream, "output.pdf");
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key128Bit;

security.Algorithm = PdfEncryptionAlgorithm.RC4;

security.UserPassword = "password";

graphics.DrawString("Encrypted with RC4 128bit", font, brush, new PointF(0, 40));

//Save the document into stream.

MemoryStream stream = new MemoryStream();

document.Save(stream);

stream.Position = 0;

//Close the documents.

document.Close(true);

//Defining the ContentType for pdf file.

string contentType = "application/pdf";

//Define the file name.

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name.

return File(stream, contentType, fileName);
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key128Bit;

security.Algorithm = PdfEncryptionAlgorithm.RC4;

security.UserPassword = "password";

graphics.DrawString("Encrypted with RC4 128bit", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

document.Save(stream);

//Closes the document

document.Close(true);

//Save the stream into pdf file

//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code samples

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

NOTE

While using both user and owner passwords, please specify different user and owner password while encrypting the PDF document for better security.

You can protect the PDF document from printing, editing, copying with the OwnerPassword by using the following code snippet.

Owner password: Sets PDF document restrictions, which can include printing, content copying, editing, page extracting, commenting, and more. Once the owner password is set, Acrobat will require this password to make any changes to the PDF document. It further secures the PDF document to set a PDF Owner Password.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm.

security.KeySize = PdfEncryptionKeySize.Key128Bit;

security.Algorithm = PdfEncryptionAlgorithm.RC4;

security.OwnerPassword = "syncfusion";

//It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.AccessibilityCopyContent;

security.UserPassword = "password";

graphics.DrawString("This document is protected with owner password", font, brush, new PointF(0, 40));

//Save and close the document.

document.Save("Output.pdf");

document.Close(true);
'Create a new PDF document.

Dim document As New PdfDocument()

Dim page As PdfPage = document.Pages.Add()

Dim graphics As PdfGraphics = page.Graphics

Dim font As New PdfStandardFont(PdfFontFamily.TimesRoman, 20.0F, PdfFontStyle.Bold)

Dim brush As PdfBrush = PdfBrushes.Black

'Document security.

Dim security As PdfSecurity = document.Security

'Specifies key size and encryption algorithm using 128 bit key in RC4 mode.

security.KeySize = PdfEncryptionKeySize.Key128Bit

security.Algorithm = PdfEncryptionAlgorithm.RC4

security.OwnerPassword = "syncfusion"

'It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print Or PdfPermissionsFlags.AccessibilityCopyContent

security.UserPassword = "password"

graphics.DrawString("This document is protected with owner password", font, brush, New PointF(0, 40))

'Save and close the document.

document.Save("Output.pdf")

document.Close(True)
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm.

security.KeySize = PdfEncryptionKeySize.Key128Bit;

security.Algorithm = PdfEncryptionAlgorithm.RC4;

security.OwnerPassword = "syncfusion";

//It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.AccessibilityCopyContent;

security.UserPassword = "password";

graphics.DrawString("This document is protected with owner password", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

await document.SaveAsync(stream);

//Close the document

document.Close(true);                                                                   

//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respected code samples

Save(stream, "output.pdf");
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm.

security.KeySize = PdfEncryptionKeySize.Key128Bit;

security.Algorithm = PdfEncryptionAlgorithm.RC4;

security.OwnerPassword = "syncfusion";

//It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.AccessibilityCopyContent;

security.UserPassword = "password";

graphics.DrawString("This document is protected with owner password", font, brush, new PointF(0, 40));

//Save the document into stream.

MemoryStream stream = new MemoryStream();

document.Save(stream);

stream.Position = 0;

//Close the documents.

document.Close(true);

//Defining the ContentType for pdf file.

string contentType = "application/pdf";

//Define the file name.

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name.

return File(stream, contentType, fileName);
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm.

security.KeySize = PdfEncryptionKeySize.Key128Bit;

security.Algorithm = PdfEncryptionAlgorithm.RC4;

security.OwnerPassword = "syncfusion";

//It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.AccessibilityCopyContent;

security.UserPassword = "password";

graphics.DrawString("This document is protected with owner password", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

document.Save(stream);

//Closes the document

document.Close(true);

//Save the stream into pdf file

//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code samples

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

Working with AES Encryption

You can encrypt PDF document using AES algorithm with 40bit or 128bit or 256bit key size. The following code snippet illustrates how to encrypt the PDF document with the UserPassword.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm.

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

security.UserPassword = "password";

graphics.DrawString("Encrypted with AES 256bit", font, brush, new PointF(0, 40));

//Save and close the document.

document.Save("Output.pdf");

document.Close(true);
'Create a new PDF document.

Dim document As New PdfDocument()

Dim page As PdfPage = document.Pages.Add()

Dim graphics As PdfGraphics = page.Graphics

Dim font As New PdfStandardFont(PdfFontFamily.TimesRoman, 20.0F, PdfFontStyle.Bold)

Dim brush As PdfBrush = PdfBrushes.Black

'Document security.

Dim security As PdfSecurity = document.Security

'Specifies key size and encryption algorithm using 256 bit key in AES mode.

security.KeySize = PdfEncryptionKeySize.Key256Bit

security.Algorithm = PdfEncryptionAlgorithm.AES

security.UserPassword = "password"

graphics.DrawString("Encrypted with AES 256bit", font, brush, New PointF(0, 40))

'Save and close the document.

document.Save("Output.pdf")

document.Close(True)
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm.

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

security.UserPassword = "password";

graphics.DrawString("Encrypted with AES 256bit", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

await document.SaveAsync(stream);

//Close the document

document.Close(true);                                                                   

//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respected code samples

Save(stream, "output.pdf");
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm.

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

security.UserPassword = "password";

graphics.DrawString("Encrypted with AES 256bit", font, brush, new PointF(0, 40));

//Save the document into stream.

MemoryStream stream = new MemoryStream();

document.Save(stream);

stream.Position = 0;

//Close the documents.

document.Close(true);

//Defining the ContentType for pdf file.

string contentType = "application/pdf";

//Define the file name.

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name.

return File(stream, contentType, fileName);
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm.

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

security.UserPassword = "password";

graphics.DrawString("Encrypted with AES 256bit", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

document.Save(stream);

//Closes the document

document.Close(true);

//Save the stream into pdf file

//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code samples

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

You can protect the PDF document from printing, editing, copying with the OwnerPassword by using the following code snippet.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm using 256 bit key in AES mode.

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

security.OwnerPassword = "syncfusion";

//It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.AccessibilityCopyContent;

security.UserPassword = "password";

graphics.DrawString("This document is protected with owner password", font, brush, new PointF(0, 40));

//Save and close the document.

document.Save("Output.pdf");

document.Close(true);
'Create a new PDF document.

Dim document As New PdfDocument()

Dim page As PdfPage = document.Pages.Add()

Dim graphics As PdfGraphics = page.Graphics

Dim font As New PdfStandardFont(PdfFontFamily.TimesRoman, 20.0F, PdfFontStyle.Bold)

Dim brush As PdfBrush = PdfBrushes.Black

'Document security.

Dim security As PdfSecurity = document.Security

'Specifies key size and encryption algorithm using 256 bit key in RC4 mode.

security.KeySize = PdfEncryptionKeySize.Key256Bit

security.Algorithm = PdfEncryptionAlgorithm.AES

security.OwnerPassword = "syncfusion"

'It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print Or PdfPermissionsFlags.AccessibilityCopyContent

security.UserPassword = "password"

graphics.DrawString("This document is protected with owner password", font, brush, New PointF(0, 40))

'Save and close the document.

document.Save("Output.pdf")

document.Close(True)
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm using 256 bit key in AES mode.

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

security.OwnerPassword = "syncfusion";

//It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.AccessibilityCopyContent;

security.UserPassword = "password";

graphics.DrawString("This document is protected with owner password", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

await document.SaveAsync(stream);

//Close the document

document.Close(true);                                                                   

//Save the stream as PDF document file in local machine. Refer to PDF/UWP section for respected code samples

Save(stream, "output.pdf");
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm using 256 bit key in AES mode.

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

security.OwnerPassword = "syncfusion";

//It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.AccessibilityCopyContent;

security.UserPassword = "password";

graphics.DrawString("This document is protected with owner password", font, brush, new PointF(0, 40));

//Save the document into stream.

MemoryStream stream = new MemoryStream();

document.Save(stream);

stream.Position = 0;

//Close the documents.

document.Close(true);

//Defining the ContentType for pdf file.

string contentType = "application/pdf";

//Define the file name.

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name.

return File(stream, contentType, fileName);
//Create a new PDF document.

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security.

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm using 256 bit key in AES mode.

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

security.OwnerPassword = "syncfusion";

//It allows printing and accessibility copy content

security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.AccessibilityCopyContent;

security.UserPassword = "password";

graphics.DrawString("This document is protected with owner password", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

document.Save(stream);

//Closes the document

document.Close(true);

//Save the stream into pdf file

//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code samples

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

Encryption Options

Now, the Syncfusion PDF library has provided options to encrypt the PDF document as follows:

Encrypt all contents – All contents of the document will be encrypted.
Encrypt all contents except Metadata – All contents of the document will be encrypted except metadata.
Encrypt only attachments – Encrypts only the file attachments, rest of the document will be left unencrypted.

The default value of EncryptionOptions is EncryptAllContents. You can choose any one of these options using the property “EncryptionOptions” available in the class PdfSecurity.

Encrypt all contents

You can encrypt all the PDF content by using the EncryptAllContents option available in the EncryptionOptions. The following code snippet explains how to encrypt all contents of the PDF document.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContents;

security.UserPassword = "password";

graphics.DrawString("Encrypted with AES 256bit", font, brush, new PointF(0, 40));

//Save and close the document

document.Save("Output.pdf");

document.Close();
'Create a new PDF document

Dim document As New PdfDocument()

Dim page As PdfPage = document.Pages.Add()

Dim graphics As PdfGraphics = page.Graphics

Dim font As New PdfStandardFont(PdfFontFamily.TimesRoman, 20.0F, PdfFontStyle.Bold)

Dim brush As PdfBrush = PdfBrushes.Black

'Document security

Dim security As PdfSecurity = document.Security

'Specifies key size and encryption algorithm using 256 bit key in AES mode

security.KeySize = PdfEncryptionKeySize.Key256Bit

security.Algorithm = PdfEncryptionAlgorithm.AES

'Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContents;

security.UserPassword = "password"

graphics.DrawString("Encrypted with AES 256bit", font, brush, New PointF(0, 40))        

'Save and close the document

document.Save("Output.pdf")

document.Close()
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContents;

security.UserPassword = "password";

graphics.DrawString("Encrypted with AES 256bit", font, brush, new PointF(0, 40));

//Save the PDF document to stream 
 
MemoryStream stream = new MemoryStream(); 

await document.SaveAsync(stream); 

//Close the document

document.Close(true);

//Save the stream as PDF document file in local machine. Refer to the PDF/UWP section for respective code samples

Save(stream, "Output.pdf");
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContents;

security.UserPassword = "password";

graphics.DrawString("Encrypted with AES 256bit", font, brush, new PointF(0, 40));                        

//Save the document into stream

MemoryStream stream = new MemoryStream(); 

document.Save(stream); stream.Position = 0;

//Close the documents 
 
document.Close(true);

//Defining the ContentType for pdf file 

string contentType = "application/pdf"; 

//Define the file name 

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name

return File(stream, contentType, fileName);
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContents;

security.UserPassword = "password";

graphics.DrawString("Encrypted with AES 256bit", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream(); 

document.Save(stream); 

//Closes the document 

document.Close(true);

//Save the stream into pdf file //The operation in Save under Xamarin varies between Windows Phone, Android, and iOS platforms. Refer to the PDF/Xamarin section for respective code samples 

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
} 
else 
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

Encrypt all contents except metadata

The Syncfusion Essential PDF library now supports encrypting the PDF document except the document information (metadata) by using the EncryptAllContentsExceptMetadata option. The document information will not be encrypted when using this EncryptionOption.

The following code snippet explains how to encrypt all contents except metadata of the PDF document.

NOTE

Encrypt all contents except metadata is only supported in AES algorithms with 128bit, 256bit, and 256bit revision6 key size

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContentsExceptMetadata;

security.UserPassword = "password";

graphics.DrawString("Encrypted all contents except metadata with AES 256bit", font, brush, new PointF(0, 40));

//Save and close the document

document.Save("Output.pdf");

document.Close();
'Create a new PDF document

Dim document As New PdfDocument()

Dim page As PdfPage = document.Pages.Add()

Dim graphics As PdfGraphics = page.Graphics

Dim font As New PdfStandardFont(PdfFontFamily.TimesRoman, 20.0F, PdfFontStyle.Bold)

Dim brush As PdfBrush = PdfBrushes.Black

'Document security

Dim security As PdfSecurity = document.Security

'Specifies key size and encryption algorithm using 256 bit key in AES mode

security.KeySize = PdfEncryptionKeySize.Key256Bit

security.Algorithm = PdfEncryptionAlgorithm.AES

'Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContentsExceptMetadata

security.UserPassword = "password"

graphics.DrawString("Encrypted all contents except metadata with AES 256bit", font, brush, New PointF(0, 40))        

'Save and close the document

document.Save("Output.pdf")

document.Close()
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContentsExceptMetadata;

security.UserPassword = "password";

graphics.DrawString("Encrypted with all contents except metadata AES 256bit", font, brush, new PointF(0, 40));

//Save the PDF document to stream 
 
MemoryStream stream = new MemoryStream(); 

await document.SaveAsync(stream); 

//Close the document

document.Close(true);

//Save the stream as PDF document file in local machine. Refer to the PDF/UWP section for respective code samples

Save(stream, "Output.pdf");
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContentsExceptMetadata;

security.UserPassword = "password";

graphics.DrawString("Encrypted all contents except metadata with AES 256bit", font, brush, new PointF(0, 40));                        

//Save the document into stream

MemoryStream stream = new MemoryStream(); 

document.Save(stream); stream.Position = 0;

//Close the documents 
 
document.Close(true);

//Defining the ContentType for pdf file 

string contentType = "application/pdf"; 

//Define the file name 

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name

return File(stream, contentType, fileName);
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptAllContentsExceptMetadata;

security.UserPassword = "password";

graphics.DrawString("Encrypted all contents except metadata with AES 256bit", font, brush, new PointF(0, 40));

//Save the PDF document to stream

MemoryStream stream = new MemoryStream(); 

document.Save(stream); 

//Closes the document 

document.Close(true);

//Save the stream into pdf file //The operation in Save under Xamarin varies between Windows Phone, Android, and iOS platforms. Refer to the PDF/Xamarin section for respective code samples 

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
} 
else 
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

Encrypt only attachments

You can encrypt only attachments present in the PDF document by using the EncryptOnlyAttachments option available in the EncryptionOptions.

The following code example explains how to create an encrypt only attachment document using the Syncfusion PDF Library.

NOTE

UserPassword is mandatory for encrypt only attachments and it is only supported in AES algorithms with 128bit, 256bit, and 256bit revision6 key size

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

security.UserPassword = "password";

graphics.DrawString("Encrypted only attachments with AES 256bit", font, brush, new PointF(0, 40));

//Creates an attachment

PdfAttachment attachment = new PdfAttachment("Input.txt");

attachment.ModificationDate = DateTime.Now;

attachment.Description = "Input.txt";

attachment.MimeType = "application/txt";

//Add the attachment to the document

document.Attachments.Add(attachment);

//Save and close the document

document.Save("Output.pdf");

document.Close();
'Create a new PDF document
        
Dim document As New PdfDocument()

Dim page As PdfPage = document.Pages.Add()

Dim graphics As PdfGraphics = page.Graphics

Dim font As New PdfStandardFont(PdfFontFamily.TimesRoman, 20.0F, PdfFontStyle.Bold)

Dim brush As PdfBrush = PdfBrushes.Black

'Document security

Dim security As PdfSecurity = document.Security

'Specifies key size and encryption algorithm using 256 bit key in AES mode

security.KeySize = PdfEncryptionKeySize.Key256Bit

security.Algorithm = PdfEncryptionAlgorithm.AES

'Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

security.UserPassword = "password"

graphics.DrawString("Encrypted only attachments with AES 256bit", font, brush, New PointF(0, 40))

'Creates an attachment

Dim attachment As New PdfAttachment("Input.txt")

attachment.ModificationDate = DateTime.Now

attachment.Description = "Input.txt" 

attachment.MimeType = "application/txt" 

Add the attachment to the document

document.Attachments.Add(attachment)

'Save and close the document

document.Save("Output.pdf")

document.Close()
//Create a new PDF document
           
PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

security.UserPassword = "password";

graphics.DrawString("Encrypted only attachments with AES 256bit", font, brush, new PointF(0, 40));

//Creates an attachment

PdfAttachment attachment = new PdfAttachment("Input.txt");

attachment.ModificationDate = DateTime.Now;

attachment.Description = "Input.txt";

attachment.MimeType = "application/txt";

//Add the attachment to the document

document.Attachments.Add(attachment);

//Save the PDF document to stream 
 
MemoryStream stream = new MemoryStream(); 

await document.SaveAsync(stream); 

//Close the document

document.Close(true);

//Save the stream as PDF document file in local machine. Refer to the PDF/UWP section for respective code samples

Save(stream, "Output.pdf");
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm       

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

security.UserPassword = "password";

graphics.DrawString("Encrypted only attachments with AES 256bit", font, brush, new PointF(0, 40));

//Creates an attachment

PdfAttachment attachment = new PdfAttachment("Input.txt");

attachment.ModificationDate = DateTime.Now;

attachment.Description = "Input.txt";

attachment.MimeType = "application/txt";

//Add the attachment to the document

document.Attachments.Add(attachment);

//Save the document into stream

MemoryStream stream = new MemoryStream(); 

document.Save(stream); stream.Position = 0;

//Close the documents

document.Close(true);

//Defining the ContentType for pdf file 

string contentType = "application/pdf"; 

//Define the file name 

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name

return File(stream, contentType, fileName);
//Create a new PDF document

PdfDocument document = new PdfDocument();

PdfPage page = document.Pages.Add();

PdfGraphics graphics = page.Graphics;

PdfStandardFont font = new PdfStandardFont(PdfFontFamily.TimesRoman, 20f, PdfFontStyle.Bold);

PdfBrush brush = PdfBrushes.Black;

//Document security

PdfSecurity security = document.Security;

//Specifies key size and encryption algorithm

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

security.UserPassword = "password";

graphics.DrawString("Encrypted only attachments with AES 256bit", font, brush, new PointF(0, 40));

//Creates an attachment

PdfAttachment attachment = new PdfAttachment("Input.txt");

attachment.ModificationDate = DateTime.Now;

attachment.Description = "Input.txt";

attachment.MimeType = "application/txt";

//Add the attachment to the document

document.Attachments.Add(attachment);

//Save the PDF document to stream

MemoryStream stream = new MemoryStream(); 

document.Save(stream); 

//Closes the document 

document.Close(true);

//Save the stream into pdf file //The operation in Save under Xamarin varies between Windows Phone, Android, and iOS platforms. Refer to the PDF/Xamarin section for respective code samples 

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
} 
else 
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

Opening an encrypt-only-attachment document

The Syncfusion Essential PDF library now provides support for loading the encrypt-only-attachment PDF documents. To access the attachments in the existing PDF document, the UserPassword is mandatory.
You can provide the UserPassword in following ways:

Load the PDF document with password.
Provide password using the OnPdfPassword Event when accessing the attachments.

It is possible to access all the contents except attachment when loading the PDF document without UserPassword.

The following code example explains how to load an encrypt-only-attachment document with password using Syncfusion PDF Library.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Load the PDF document 

PdfLoadedDocument document = new PdfLoadedDocument("Input.pdf","password");
            
//Accessing the attachments             

foreach(PdfAttachment attachment in document.Attachments)
{
   FileStream stream = new FileStream(attachment.FileName, FileMode.Create);

   stream.Write(attachment.Data, 0, attachment.Data.Length);

   stream.Dispose();
}         

//Close the document 

document.Close(true);
'Load the PDF document 

Dim document As PdfLoadedDocument = New PdfLoadedDocument("Input.pdf", "password")
             
'Accessing the attachments

For Each attachment As PdfAttachment In document.Attachments

   Dim stream = New FileStream(attachment.FileName, FileMode.Create)
  
   stream.Write(attachment.Data, 0, attachment.Data.Length)

   stream.Dispose

Next

'Close the document 

document.Close(true)
//Load the PDF document as stream 

Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.Input.pdf");                                                                                                                 

//Creates an empty PDF loaded document instance 

PdfLoadedDocument document = new PdfLoadedDocument(pdfStream, "password");                       
             
//Accessing the attachments

foreach(PdfAttachment  attachment in document.Attachments)
{
   FileStream stream= new FileStream(attachment.FileName, FileMode.Create);

   stream.Write(attachment.Data, 0, attachment.Data.Length);

   stream.Dispose();
}                                

//Close the document 

document.Close(true);
//Load the PDF document 
             
FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read); 

PdfLoadedDocument document = new PdfLoadedDocument(docStream,"password");

//Accessing the attachments
         
foreach(PdfAttachment  attachment in document.Attachments)
{
   FileStream  stream = new FileStream(attachment.FileName, FileMode.Create);

   stream.Write(attachment.Data, 0, attachment.Data.Length);

   stream.Dispose();
}                      

//Close the document

document.Close(true);
//Load the PDF document as stream 

Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Input.pdf");

//Creates an empty PDF loaded document instance 

PdfLoadedDocument document = new PdfLoadedDocument(docStream,"password");                 

//Accessing the attachments

foreach(PdfAttachment  attachment in document.Attachments)
{
   FileStream  stream= new FileStream(attachment.FileName, FileMode.Create);

   stream.Write(attachment.Data, 0, attachment.Data.Length);

   stream.Dispose();
}                                 

//Close the document 

document.Close(true);

Set user password using event when accessing the attachment

The following code example illustrates how to provide the password when accessing attachments from encrypt-only-attachment document using the OnPdfPassword event.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Load the PDF document 

PdfLoadedDocument document = new PdfLoadedDocument("Input.pdf");

document.OnPdfPassword += LDoc_OnPdfPassword;

//Accessing the attachments

foreach(PdfAttachment attachment in document.Attachments)
{
   FileStream stream= new FileStream(attachment.FileName, FileMode.Create);

   stream.Write(attachment.Data, 0, attachment.Data.Length);

   stream.Dispose();
}                      

//Close the document 

document.Close(true);
	
//Provide the user password in event 

private static void LDoc_OnPdfPassword(object sender, OnPdfPasswordEventArgs args)
{
    args.UserPassword = "syncfusion";
}
'Load the PDF document 
         
Dim document As PdfLoadedDocument = New PdfLoadedDocument("Input.pdf")

'document.OnPdfPassword += LDoc_OnPdfPassword()

AddHandler document.OnPdfPassword, AddressOf LDoc_OnPdfPassword

'Accessing the attachments

For Each attachment As PdfAttachment In document.Attachments

   Dim stream As FileStream = New FileStream(attachment.FileName, FileMode.Create)
   
   stream.Write(attachment.Data, 0, attachment.Data.Length)
   
   stream.Dispose()

Next

'Close the document

document.Close(True)

'Provide the user password in event 

Private Sub LDoc_OnPdfPassword(ByVal sender As Object, ByVal args As OnPdfPasswordEventArgs)

   args.UserPassword = "password"
 
End Sub
//Load the PDF document as stream 


Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.Input.pdf");                                                                                                                 

//Creates an empty PDF loaded document instance 

PdfLoadedDocument document = new PdfLoadedDocument(pdfStream);       
                      
document.OnPdfPassword += LDoc_OnPdfPassword;

//Accessing the attachments

foreach(PdfAttachment  attachment in document.Attachments)
{
   FileStream  stream = new FileStream(attachment.FileName, FileMode.Create);

   stream.Write(attachment.Data, 0, attachment.Data.Length);

   stream.Dispose();
}                      

//Close the document 

document.Close(true);
	
//Provide the user password in event 

private static void LDoc_OnPdfPassword(object sender, OnPdfPasswordEventArgs args)
{
    args.UserPassword = "syncfusion";
}
//Load the PDF document 

FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read); 

PdfLoadedDocument document = new PdfLoadedDocument(docStream);

document.OnPdfPassword += LDoc_OnPdfPassword;

//Accessing the attachments
foreach(PdfAttachment  attachment in document.Attachments)
{
   FileStream  stream= new FileStream(attachment.FileName, FileMode.Create);

   stream.Write(attachment.Data, 0, attachment.Data.Length);

   stream.Dispose();
}                      

//Close the document 

document.Close(true);
	
//Provide the user password in event

private static void LDoc_OnPdfPassword(object sender, OnPdfPasswordEventArgs args)
{
    args.UserPassword = "syncfusion";
}
//Load the PDF document as stream 

Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Input.pdf");

//Creates an empty PDF loaded document instance 

PdfLoadedDocument document = new PdfLoadedDocument(docStream);   
    
document.OnPdfPassword += LDoc_OnPdfPassword;

// Accessing the attachments

foreach(PdfAttachment  attachment in document.Attachments)
{
   FileStream  stream= new FileStream(attachment.FileName, FileMode.Create);

   stream.Write(attachment.Data, 0, attachment.Data.Length);

   stream.Dispose();
}                      

//Close the document

document.Close(true);
	
//Provide the user password in event

private static void LDoc_OnPdfPassword(object sender, OnPdfPasswordEventArgs args)
{
    args.UserPassword = "syncfusion";
}

Protect attachments in existing PDF document

The Syncfusion PDF Library supports encrypting only the attachment files in an existing PDF document using the EncryptOnlyAttachments encryption option. Refer to the following code snippet.

NOTE

UserPassword is mandatory for this encryption option.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Load the PDF document 

PdfLoadedDocument document = new PdfLoadedDocument("Input.pdf");

//PDF document security

PdfSecurity security = document.Security; 

//Specifies encryption key size, algorithm and permission

security.KeySize = PdfEncryptionKeySize.Key256Bit; 

security.Algorithm = PdfEncryptionAlgorithm.AES; 

//Provide user password

security.UserPassword = "password";

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

//Save the document

document.Save("Output.pdf");

//Close the document 

document.Close(true);
'Load the PDF document 
             
Dim document As New PdfLoadedDocument("Input.pdf")

'PDF document security

Dim security As PdfSecurity = document.Security

'Specifies encryption key size, algorithm and permission

security.KeySize = PdfEncryptionKeySize.Key256Bit

security.Algorithm = PdfEncryptionAlgorithm.AES

'Provide user password

security.UserPassword = "password"

'Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments

'Save the document

document.Save("Output.pdf")

'Close the document

document.Close(true)
//Load the PDF document as stream 

Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.Input.pdf");                                                                                                                

//Creates an empty PDF loaded document instance 

PdfLoadedDocument document = new PdfLoadedDocument(pdfStream);       

//PDF document security

PdfSecurity security = document.Security; 

//Specifies encryption key size, algorithm and permission

security.KeySize = PdfEncryptionKeySize.Key256Bit; 

security.Algorithm = PdfEncryptionAlgorithm.AES; 

//Provide user password

security.UserPassword = "password";

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

//Save the PDF document to stream 

MemoryStream stream = new MemoryStream(); 

await document.SaveAsync(stream); 

//Close the document

document.Close(true);

//Save the stream as PDF document file in local machine. Refer to the PDF/UWP section for respective code samples
 
Save(stream, "Output.pdf");
//Load the PDF document 

FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read); 

PdfLoadedDocument document = new PdfLoadedDocument(docStream);

//PDF document security

PdfSecurity security = document.Security; 

//Specifies encryption key size, algorithm and permission

security.KeySize = PdfEncryptionKeySize.Key256Bit; 

security.Algorithm = PdfEncryptionAlgorithm.AES; 

//Provide user password

security.UserPassword = "password";

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

//Save the document into stream

MemoryStream stream = new MemoryStream(); 

document.Save(stream); stream.Position = 0;

//Close the documents

document.Close(true);

//Defining the ContentType for pdf file 

string contentType = "application/pdf"; 

//Define the file name

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name

return File(stream, contentType, fileName);
//Load the PDF document as stream 

Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Input.pdf");

//Creates an empty PDF loaded document instance 

PdfLoadedDocument document = new PdfLoadedDocument(docStream);       

//PDF document security

PdfSecurity security = document.Security; 

//Specifies encryption key size, algorithm and permission

security.KeySize = PdfEncryptionKeySize.Key256Bit; 

security.Algorithm = PdfEncryptionAlgorithm.AES; 

//Provide user password

security.UserPassword = "password";

//Specifies encryption option

security.EncryptionOptions = PdfEncryptionOptions.EncryptOnlyAttachments;

//Save the PDF document to stream

MemoryStream stream = new MemoryStream(); 

document.Save(stream); 

//Closes the document 

document.Close(true);
 
//Save the stream into pdf file //The operation in Save under Xamarin varies between Windows Phone, Android, and iOS platforms. Refer to the PDF/Xamarin section for respective code samples 

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
     Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
} 
else 
{
     Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

Protect an existing document

You can protect an existing PDF document with both UserPassword and OwnerPassword by using the following code snippet.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Load the PDF document

PdfLoadedDocument document = new PdfLoadedDocument("Input.pdf");

//PDF document security 

PdfSecurity security = document.Security;

//Specifies encryption key size, algorithm and permission. 

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

 //Provide owner and user password.

 security.OwnerPassword = "ownerPassword256";

 security.UserPassword = "userPassword256";

 //Save the document.

 document.Save("Output.pdf");

//Close the document.

document.Close(true);
'Load an existing document.

 Dim document As New PdfLoadedDocument("Input.pdf")

'Document Security

Dim security As PdfSecurity = document.Security

'Specifies key size and encryption algorithm

 security.KeySize = PdfEncryptionKeySize.Key128Bit

security.Algorithm = PdfEncryptionAlgorithm.RC4

'Provide owner and user password.

security.OwnerPassword = "ownerPassword256"

security.UserPassword = "userPassword256"

'Save the document.

document.Save("Output.pdf")

'Close the document.

document.Close(True)
//Load the PDF document as stream

Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.Input.pdf");

//Creates an empty PDF loaded document instance

PdfLoadedDocument document = new PdfLoadedDocument(pdfStream);

//PDF document security 

PdfSecurity security = document.Security;

//Specifies encryption key size, algorithm and permission. 

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Provide owner and user password.

security.OwnerPassword = "ownerPassword256";

security.UserPassword = "userPassword256";

MemoryStream memoryStream = new MemoryStream();

//Save the document.

document.Save(memoryStream);

//Close the documents.

document.Close(true);

//Save the stream as PDF document file in local machine. Refer to pdf/uwp section for respected code samples.

Save(memoryStream, "Output.pdf");
//Load the PDF document

FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read);

PdfLoadedDocument document = new PdfLoadedDocument(docStream);

//PDF document security 

PdfSecurity security = document.Security;

//Specifies encryption key size, algorithm and permission. 

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Provide owner and user password.

security.OwnerPassword = "ownerPassword256";

security.UserPassword = "userPassword256";

//Save the document into stream.

MemoryStream stream = new MemoryStream();

document.Save(stream);

stream.Position = 0;

//Close the documents.

document.Close(true);

//Defining the ContentType for pdf file.

string contentType = "application/pdf";

//Define the file name.

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name.

return File(stream, contentType, fileName);
//Load the file as stream

Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Input.pdf");

PdfLoadedDocument document = new PdfLoadedDocument(docStream);

//PDF document security 

PdfSecurity security = document.Security;

//Specifies encryption key size, algorithm and permission. 

security.KeySize = PdfEncryptionKeySize.Key256Bit;

security.Algorithm = PdfEncryptionAlgorithm.AES;

//Provide owner and user password.

security.OwnerPassword = "ownerPassword256";

security.UserPassword = "userPassword256";

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

document.Save(stream);

//Closes the document

document.Close(true);

//Save the stream into pdf file

//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code samples

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

Changing the password of the PDF document

You can change the UserPassword of the existing PDF document by using following code snippet.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Load the password protected PDF document

PdfLoadedDocument loadedDocument = new PdfLoadedDocument("Input.pdf","password");

//Change the user password 

loadedDocument.Security.UserPassword = "NewPassword";

//Save the password changed PDF document

loadedDocument.Save("Output.pdf");

loadedDocument.Close(true);
'Load the password protected PDF document

Dim loadedDocument As New PdfLoadedDocument("Input.pdf", "password")

'Change the user password 

loadedDocument.Security.UserPassword = "NewPassword"

'Save the password changed PDF document

loadedDocument.Save("Output.pdf")

loadedDocument.Close(True)
//Load the PDF document as stream

Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.Input.pdf");

//Creates an empty PDF loaded document instance

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(pdfStream,"password");

//Change the user password 

loadedDocument.Security.UserPassword = "NewPassword";

MemoryStream memoryStream = new MemoryStream();

//Save the document.

loadedDocument.Save(memoryStream);

//Close the documents.

loadedDocument.Close(true);

//Save the stream as PDF document file in local machine. Refer to pdf/uwp section for respected code samples.

Save(memoryStream, "Output.pdf");
//Load the PDF document

FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read);

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream, "password");

//Change the user password 

loadedDocument.Security.UserPassword = "NewPassword";

//Save the document into stream.

MemoryStream stream = new MemoryStream();

loadedDocument.Save(stream);

stream.Position = 0;

//Close the documents.

loadedDocument.Close(true);

//Defining the ContentType for pdf file.

string contentType = "application/pdf";

//Define the file name.

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name.

return File(stream, contentType, fileName);
//Load the file as stream

Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Input.pdf");

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream, "password");

//Change the user password 

loadedDocument.Security.UserPassword = "NewPassword";

//Save the PDF document to stream

MemoryStream stream = new MemoryStream();

loadedDocument.Save(stream);

//Closes the document

loadedDocument.Close(true);

//Save the stream into pdf file

//The operation in Save under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer PDF/Xamarin section for respective code samples

if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("sample.pdf", "application/pdf", stream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("sample.pdf", "application/pdf", stream);
}

Change the permission of the PDF document

You can change the permission of the PDF document using the Permissions. The following code snippet illustrates the same.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Load the password protected PDF document

PdfLoadedDocument loadedDocument = new PdfLoadedDocument("Input.pdf", "syncfusion");

//Change the permission

loadedDocument.Security.Permissions = PdfPermissionsFlags.CopyContent | PdfPermissionsFlags.AssembleDocument;

//Save the PDF document

loadedDocument.Save("Output.pdf");

loadedDocument.Close(true);
'Load the password protected PDF document

Dim loadedDocument As New PdfLoadedDocument("Input.pdf", "syncfusion")

'Change the permission

loadedDocument.Security.Permissions = PdfPermissionsFlags.CopyContent Or PdfPermissionsFlags.AssembleDocument

'Save the PDF document

loadedDocument.Save("Output.pdf")

loadedDocument.Close(True)
//Load the PDF document as stream

Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.Input.pdf");

//Creates an empty PDF loaded document instance

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(pdfStream,"syncfusion");

//Change the permission

loadedDocument.Security.Permissions = PdfPermissionsFlags.CopyContent | PdfPermissionsFlags.AssembleDocument;

MemoryStream memoryStream = new MemoryStream();

//Save the document.

loadedDocument.Save(memoryStream);

//Close the documents.

loadedDocument.Close(true);

//Save the stream as PDF document file in local machine. Refer to pdf/uwp section for respected code samples.

Save(memoryStream, "Output.pdf");
//Load the PDF document

FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read);

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream, "syncfusion");

//Change the permission

loadedDocument.Security.Permissions = PdfPermissionsFlags.CopyContent | PdfPermissionsFlags.AssembleDocument;

//Save the document into stream.

MemoryStream stream = new MemoryStream();

loadedDocument.Save(stream);

stream.Position = 0;

//Close the documents.

loadedDocument.Close(true);

//Defining the ContentType for pdf file.

string contentType = "application/pdf";

//Define the file name.

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name.

return File(stream, contentType, fileName);
//Load the file as stream

Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Input.pdf");

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream,"syncfusion");

//Change the permission

loadedDocument.Security.Permissions = PdfPermissionsFlags.CopyContent | PdfPermissionsFlags.AssembleDocument;

//document.Attachments.RemoveAt(1);

//Save the document into stream.

MemoryStream memoryStream = new MemoryStream();

loadedDocument.Save(memoryStream);

//Close the documents.

loadedDocument.Close(true);

//Save the stream into pdf file

//The operation in SaveAndView under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer pdf/xamarin section for respective code samples.
if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("Output.pdf", "application/pdf", memoryStream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("Output.pdf", "application/pdf", memoryStream);
}

Remove password from the user password PDF document

You can remove the UserPassword from the encrypted PDF document by using the following code snippet.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
//Load the password protected PDF document

PdfLoadedDocument loadedDocument = new PdfLoadedDocument("Input.pdf","password");

//Change the user password 

loadedDocument.Security.UserPassword = string.Empty;

//Save the password removed PDF document

loadedDocument.Save("Output.pdf");

loadedDocument.Close(true);
'Load the password protected PDF document

Dim loadedDocument As New PdfLoadedDocument("Input.pdf", "password")

'Change the user password 

loadedDocument.Security.UserPassword = String.Empty

'Save the password removed PDF document

loadedDocument.Save("Output.pdf")

loadedDocument.Close(True)
//Load the PDF document as stream

Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.Input.pdf");

//Creates an empty PDF loaded document instance

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(pdfStream,"password");

//Change the user password 

loadedDocument.Security.UserPassword = string.Empty;

MemoryStream memoryStream = new MemoryStream();

//Save the document.

loadedDocument.Save(memoryStream);

//Close the documents.

loadedDocument.Close(true);

//Save the stream as PDF document file in local machine. Refer to pdf/uwp section for respected code samples.

Save(memoryStream, "Output.pdf");
//Load the PDF document

FileStream docStream = new FileStream("Input.pdf", FileMode.Open, FileAccess.Read);

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream, "password");

//Change the user password 

loadedDocument.Security.UserPassword = string.Empty;

//Save the document into stream.

MemoryStream stream = new MemoryStream();

loadedDocument.Save(stream);

stream.Position = 0;

//Close the documents.

loadedDocument.Close(true);

//Defining the ContentType for pdf file.

string contentType = "application/pdf";

//Define the file name.

string fileName = "Output.pdf";

//Creates a FileContentResult object by using the file contents, content type, and file name.

return File(stream, contentType, fileName);
//Load the file as stream

Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Input.pdf");

PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream,"password");

//Change the user password 

loadedDocument.Security.UserPassword = string.Empty;

//Save the document into stream.

MemoryStream memoryStream = new MemoryStream();

loadedDocument.Save(memoryStream);

//Close the documents.

loadedDocument.Close(true);

//Save the stream into pdf file

//The operation in SaveAndView under Xamarin varies between Windows Phone, Android and iOS platforms. Please refer pdf/xamarin section for respective code samples.
if (Device.OS == TargetPlatform.WinPhone || Device.OS == TargetPlatform.Windows)
{
    Xamarin.Forms.DependencyService.Get<ISaveWindowsPhone>().Save("Output.pdf", "application/pdf", memoryStream);
}
else
{
    Xamarin.Forms.DependencyService.Get<ISave>().Save("Output.pdf", "application/pdf", memoryStream);
}

How to determine whether the PDF document is password protected or not?

You can determine whether the existing PDF document is password protected or not by catching the PdfDocumentException as shown below.

C#
VB.NET
UWP
ASP.NET Core
Xamarin
try
{
	//Load the password protected PDF document without user password
	PdfLoadedDocument loadedDocument = new PdfLoadedDocument("Output.pdf");
}
catch (PdfDocumentException exception)
{
	if (exception.Message == "Can't open an encrypted document. The password is invalid.")
	{
		MessageBox.Show("Cannot open an encrypted document without password");
	}
}
Try
	'Load the password protected PDF document without user password
	Dim loadedDocument As New PdfLoadedDocument("Output.pdf")
Catch exception As PdfDocumentException
	If exception.Message = "Can't open an encrypted document. The password is invalid." Then
		MessageBox.Show("Cannot open an encrypted document without password")
	End If
End Try
try
{
    //Load the PDF document as stream

    Stream pdfStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Data.Output.pdf");

    //Creates an empty PDF loaded document instance

    PdfLoadedDocument loadedDocument = new PdfLoadedDocument(pdfStream);

}

catch (PdfDocumentException exception)
{
    
}
try

{
    //Load the PDF document

    FileStream docStream = new FileStream("Output.pdf", FileMode.Open, FileAccess.Read);

    PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream);

}

catch (PdfDocumentException exception)
{
    
}
try
{
    //Load the file as stream

    Stream docStream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("Sample.Assets.Output.pdf");

    PdfLoadedDocument loadedDocument = new PdfLoadedDocument(docStream);
}

catch (PdfDocumentException exception)
{
   
}

How to determine whether the PDF document is protected by user or owner password

Essential PDF supports identifying the document whether it is protected by user or owner.

The following table shows the various combination for loading the secured document with user or owner password:

Document type	Open with	User password	Owner password
PDF document secured with both the owner and user passwords.	User password	Returns user password	Returns null
PDF document secured with both the owner and user passwords.	Owner password	Returns user password Note: Returns null for AES 256 and AES 256 Revision 6 encryptions.	Returns owner password
PDF document secured with owner password alone.	Owner password	Returns null	Returns owner password
PDF document secured with user password alone.	User Password	Returns user password	Returns owner Password (owner password is same as the user password; it allows full permission to users).