encryption pdf file and decryption in c#

       static void EncryptPDF()
        {
	    //Create a pdf document.
	    PdfDocument doc = new PdfDocument();
	    // Create one page
	    PdfPageBase page = doc.Pages.Add();
	    //Draw the page
	    DrawPage(page);
 
	    //encrypt
	    doc.Security.KeySize = PdfEncryptionKeySize.Key128Bit;
	    doc.Security.OwnerPassword = "e-iceblue";
	    doc.Security.UserPassword = "test";
	    doc.Security.Permissions = PdfPermissionsFlags.Print | PdfPermissionsFlags.FillFields;
 
	    doc.SaveToFile("Encryption.pdf");
	    doc.Close();
 
	    //Launching the Pdf file.
	     System.Diagnostics.Process.Start("Encryption.pdf");
	 }