Create A Password Protected PDF in ASP.NET Core

Passwords can ensure that only the people who need to review a document can open and make changes to it if you need to adhere to a strict process. Locking documents can also prevent form edits in PDFs.

By password-protecting a Word or PDF document, you can keep private and sensitive information safe. This encrypts the file’s contents, making it inaccessible to anyone without entering the password.

Step 1 : First, let’s open Visual Studio and create a new project

Step 2 : Install Nuget package iTextSharp

Step 3 : Copy and Paste below code in view to create a button

<div class="text-center">
    @Html.ActionLink("Oepn PDF", "OpenPDF", "Home", null, new { @class = "btn btn-primary btn-large" })
</div>

Step 4 : Define the path of PDF in the appsetting.json file and read the in controller

In appsetting.json

"File": {
    "Path": "C:\\Users\\pc3\\Desktop\\PasswordProtectedPDF\\PDF\\Funday.pdf"
  }

Read path from appsetting.json

using Microsoft.Extensions.Configuration;

public static IConfiguration _configuration;
public HomeController(IConfiguration configuration)
 {
   _configuration = configuration;
 }

Step 5 : Copy and paste the below code into your controller

using Microsoft.Extensions.Configuration; 

public static IConfiguration _configuration;
public HomeController(IConfiguration configuration)
{        
   _configuration = configuration;
}
public ActionResult OpenPDF()
 {
    var pathToFile = _configuration.GetSection("File").GetSection("Path").Value;
           
    byte[] bytes = System.IO.File.ReadAllBytes(pathToFile);
    using (MemoryStream inputData = new MemoryStream(bytes))
       {
          using (MemoryStream outputData = new MemoryStream())
             {
                 string PDFFilepassword = "niki@123";
                 PdfReader reader = new PdfReader(inputData);
                 PdfReader.unethicalreading = true;
                 PdfEncryptor.Encrypt(reader, outputData, true, PDFFilepassword, PDFFilepassword, PdfWriter.ALLOW_SCREENREADERS);
                 bytes = outputData.ToArray();
                 return File(bytes, "application/pdf");
              }
        }
 }

OUTPUT