How to decrypt a PDF File and Disable its Password in C# .NET Framework

PDF decryption is not as easy to accomplish as you may think at initial glance. I won’t get into all the messy details, but suffice to say, this is actually quite a challenging feature to implement. With that in mind, I am here with today’s tutorial, which will get you all set up with PDF decryption in but a few minutes.

First we need our package:

Install-Package Cloudmersive.APIClient.NET.DocumentAndDataConvert -Version 3.2.8

Now we will call this function, providing our PDF file and the password to use to decrypt it:

using System;
using System.Diagnostics;
using Cloudmersive.APIClient.NET.DocumentAndDataConvert.Api;
using Cloudmersive.APIClient.NET.DocumentAndDataConvert.Client;
using Cloudmersive.APIClient.NET.DocumentAndDataConvert.Model;
namespace Example
{
public class EditPdfDecryptExample
{
public void main()
{
// Configure API key authorization: Apikey
Configuration.Default.AddApiKey("Apikey", "YOUR_API_KEY");
// Uncomment below to setup prefix (e.g. Bearer) for API key, if needed
// Configuration.Default.AddApiKeyPrefix("Apikey", "Bearer");
var apiInstance = new EditPdfApi();
var password = password_example;  // string | Valid password for the PDF file
var inputFile = new System.IO.Stream(); // System.IO.Stream | Input file to perform the operation on.
try
{
// Decrypt and password-protect a PDF
byte[] result = apiInstance.EditPdfDecrypt(password, inputFile);
Debug.WriteLine(result);
}
catch (Exception e)
{
Debug.Print("Exception when calling EditPdfApi.EditPdfDecrypt: " + e.Message );
}
}
}
}

And that’s really all there is to it.