How to decrypt pdf file by providing file password as argument using C #?

Question

I created a password protected pdf file using the following code:

using (Stream input = new FileStream(InputFile, FileMode.Open, FileAccess.Read, FileShare.Read)) { using (Stream output = new FileStream(OutputFile, FileMode.Create, FileAccess.Write, FileShare.None)) { PdfReader reader = new PdfReader(input); PdfEncryptor.Encrypt(reader, output, true, strDob, "secret", PdfWriter.ALLOW_SCREENREADERS); } } 

I want to remove the password for a PDF file generated using the above code, based on my specific conditions through the code.

Answer 1

 string WorkingFolder = Environment.GetFolderPath(Environment.SpecialFolder.Desktop); string InputFile = Path.Combine(WorkingFolder, "test.pdf"); string OutputFile = Path.Combine(WorkingFolder, "test_dec.pdf");//will be created automatically //You must provide owner password but not the user password . private void DecryptFile(string inputFile, string outputFile) { string password = @"secret"; // Your Key Here try { PdfReader reader = new PdfReader(inputFile, new System.Text.ASCIIEncoding().GetBytes(password)); using (MemoryStream memoryStream = new MemoryStream()) { PdfStamper stamper = new PdfStamper(reader, memoryStream); stamper.Close(); reader.Close(); File.WriteAllBytes(outputFile, memoryStream.ToArray()); } } catch (Exception err) { Console.WriteLine(err.Message); } }