Password Protected File Validation for(.doc/.docx/.xls/.xlsx/.pdf) file types

Password Protected File Validation for(.doc/.docx/.xls/.xlsx/.pdf) file types

protected void btnUpload_Click(object sender, EventArgs e)

        {

            //Check if File Upload control has file or not

            if (FileUpload1.HasFile)

            {

                //Get Uploaded file bytes

                var bytes = FileUpload1.FileBytes;

                //Get Uploaded File Extension

                FileInfo objFileInfo = new FileInfo(FileUpload1.FileName);

                string StrFileExt = objFileInfo.Extension.ToUpper();

               

                //Based on the File extension call appropriate user defined method.

                //For PDF file type

                if (StrFileExt == ".PDF")

                {

                    //Upload and save file in server temp folder

                    var newfilename = DateTime.Now.GetHashCode() + FileUpload1.FileName;

                    FileUpload1.SaveAs(System.Web.Hosting.HostingEnvironment.MapPath("~/UploadedFiles/" + newfilename));

                    //Validate Password Protected PDF.

                    if (IsPasswordProtectedPDF(newfilename))

                    {

                        ShowMsg(true);

                    }

                    else

                    {

                        ShowMsg(false);

                    }

                }

                //For Word and Excel file types

                else if ((StrFileExt == ".DOC") || (StrFileExt == ".DOCX") || (StrFileExt == ".XLS") || (StrFileExt == ".XLSX"))

                {

                    if (IsPassworded(bytes))

                    {

                        ShowMsg(true);

                    }

                    else

                    {

                        ShowMsg(false);

                    }

                }

                //Show msg on invalid file upload

                else

                {

                    lblmsg.Text = "Invalid file format!!!";

                    lblmsg.ForeColor = System.Drawing.Color.Red;

                }

            }

        }

public static bool IsPasswordProtectedPDF(string strNewFileName)

        {

            try

            {

                PdfDocument document = PdfReader.Open(System.Web.Hosting.HostingEnvironment.MapPath("~/UploadedFiles/" + strNewFileName), "1234");

                return false;

            }

            catch (PdfReaderException)

            {

                return true;

            }

        }

       

        public void ShowMsg(bool status)

        {

            if (status)

            {

                lblmsg.Text = "Yes, It's password protected!!";

                lblmsg.ForeColor = System.Drawing.Color.Red;

            }

            else

            {

                lblmsg.Text = "No, It's not password protected!!";

                lblmsg.ForeColor = System.Drawing.Color.Green;

            }

        }

        public static bool IsPassworded(byte[] bytes)

        {

            var prefix = Encoding.Default.GetString(bytes.Take(2).ToArray());

            if (prefix == "ÐÏ")

            {

                //Office format.

                //Flagged with password

                if (bytes.Skip(0x20c).Take(1).ToArray()[0] == 0x2f) return true; //XLS 2003

                if (bytes.Skip(0x214).Take(1).ToArray()[0] == 0x2f) return true; //XLS 2005

                if (bytes.Skip(0x20B).Take(1).ToArray()[0] == 0x13) return true; //DOC 2005

                if (bytes.Length < 2000) return false; //Guessing false

                var start = Encoding.Default.GetString(bytes.Take(2000).ToArray()); //DOC/XLS 2007+

                start = start.Replace("\0", " ");

                if (start.Contains("E n c r y p t e d P a c k a g e")) return true;

                return false;

            }

            //Unknown.

            return false;

        }