iTextSharp.text.pdf.PdfEncryptor.Encrypt C# (CSharp) Метод

        public static void Encrypt(PdfReader reader, Stream os, bool strength, String userPassword, String ownerPassword, int permissions)
        {
            PdfStamper stamper = new PdfStamper(reader, os);
            stamper.SetEncryption(strength, userPassword, ownerPassword, permissions);
            stamper.Close();
        }