Adjust the Password Security Settings using C# and .NET

In today's digital age, securing sensitive information is paramount. One effective way to protect your PDF documents is by implementing password protection. This article will guide you through the process of changing the password protection of a PDF document using C# and .NET, leveraging the powerful capabilities of SautinSoft.PDF library.

Password protection ensures that only authorized individuals can access the contents of your PDF documents. This is particularly important for documents containing confidential information, such as financial records, personal data, or proprietary business information.

Step-by-step guide:

  1. Add SautinSoft.PDF from NuGet.
  2. Load PDF document from a potentially encrypted PDF file.
  3. Remove encryption from an output PDF file.
  4. Set password-based encryption with password required to open a PDF document.
  5. Save PDF document to an unencrypted PDF file.

Output result:

Complete code

using System;
using SautinSoft.Pdf;
using System.IO;
using SautinSoft.Pdf.Security;

class Program
{
    /// <summary>
    /// Change the Password Protection.
    /// </summary>
    /// <remarks>
    /// Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/change-password-protection.php
    /// </remarks>
    static void Main()
    {
            // Before starting this example, please get a free 100-day trial key:
            // https://sautinsoft.com/start-for-free/

            // Apply the key here:
            // PdfDocument.SetLicense("...");
        try
        {
            // Load PDF document from a potentially encrypted PDF file.
            using (var document = PdfDocument.Load(Path.GetFullPath(@"..\..\..\hello.pdf"),
                new PdfLoadOptions() { Password = "123456" }))
            {
                // Remove encryption from an output PDF file.
                document.SaveOptions.Encryption = null;

                // Set password-based encryption with password required to open a PDF document.
                document.SaveOptions.SetPasswordEncryption().DocumentOpenPassword = "654321";

                // Save PDF document to an unencrypted PDF file.
                document.Save("Decryption.pdf");
            }
        }
        catch (InvalidPdfPasswordException ex)
        {
            // Gracefully handle the case when input PDF file is encrypted 
            // and provided password is invalid.
            Console.WriteLine(ex.Message);
        }
        System.Diagnostics.Process.Start(new System.Diagnostics.ProcessStartInfo("Decryption.pdf") { UseShellExecute = true });
    }
}

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Option Infer On

Imports System
Imports SautinSoft.Pdf
Imports System.IO
Imports SautinSoft.Pdf.Security

Friend Class Program
	''' <summary>
	''' Change the Password Protection.
	''' </summary>
	''' <remarks>
	''' Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/change-password-protection.php
	''' </remarks>
	Shared Sub Main()
			' Before starting this example, please get a free 100-day trial key:
			' https://sautinsoft.com/start-for-free/

			' Apply the key here:
			' PdfDocument.SetLicense("...");
		Try
			' Load PDF document from a potentially encrypted PDF file.
			Using document = PdfDocument.Load(Path.GetFullPath("..\..\..\hello.pdf"), New PdfLoadOptions() With {.Password = "123456"})
				' Remove encryption from an output PDF file.
				document.SaveOptions.Encryption = Nothing

				' Set password-based encryption with password required to open a PDF document.
				document.SaveOptions.SetPasswordEncryption().DocumentOpenPassword = "654321"

				' Save PDF document to an unencrypted PDF file.
				document.Save("Decryption.pdf")
			End Using
		Catch ex As InvalidPdfPasswordException
			' Gracefully handle the case when input PDF file is encrypted 
			' and provided password is invalid.
			Console.WriteLine(ex.Message)
		End Try
		System.Diagnostics.Process.Start(New System.Diagnostics.ProcessStartInfo("Decryption.pdf") With {.UseShellExecute = True})
	End Sub
End Class

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