如何使用 Open XML 密码保护 Excel 文档

Question

At the moment, I am creating a new Excel document with Open XML's SpreadsheetDocument class by passing a MemoryStream parameter. I now need to set a password on this SpreadsheetDocument object, but what I have attempted does not seem to work. The Excel document open's up without asking for a password. Below is what I have tried so far ( mem being the MemoryStream parameter):

using (SpreadsheetDocument spreadsheet = SpreadsheetDocument.Open(mem, true))
{
    foreach (var sheet in spreadsheet.WorkbookPart.WorksheetParts)
    {
        sheet.Worksheet.Append(new SheetProtection() { Password = "test" });
    }
}

I have also attempted the following with no success:

using (SpreadsheetDocument spreadsheet = SpreadsheetDocument.Open(mem, true))
{
    spreadsheet.WorkbookPart.Workbook.WorkbookProtection = new WorkbookProtection
    {
        LockStructure = true,
        LockWindows = true,
        WorkbookPassword = "test"
    }
}

What am I missing please?

Answer 1

Openxml sheet protect Password has input Data type of "HexBinaryValue". so the input password as to be converted from string to hexa binary.

foreach (var worksheetPart in spreadsheet.WorkbookPart.WorksheetParts)
     {
         //Call the method to convert the Password string "MyPasswordfor sheet" to hexbinary type
         string hexConvertedPassword =  HexPasswordConversion("MyPasswordfor sheet");
//passing the Converted password to sheet protection
          SheetProtection sheetProt = new SheetProtection() { Sheet = true, Objects = true, Scenarios = true, Password = hexConvertedPassword };
          worksheetPart.Worksheet.InsertAfter(sheetProt,worksheetPart.Worksheet.Descendants<SheetData>().LastOrDefault());
worksheetPart.Worksheet.Save();
     }


/* This method will convert the string password to hexabinary value */
 protected string HexPasswordConversion(string password)
        {
            byte[] passwordCharacters = System.Text.Encoding.ASCII.GetBytes(password);
            int hash = 0;
            if (passwordCharacters.Length > 0)
            {
                int charIndex = passwordCharacters.Length;

                while (charIndex-- > 0)
                {
                    hash = ((hash >> 14) & 0x01) | ((hash << 1) & 0x7fff);
                    hash ^= passwordCharacters[charIndex];
                }
                // Main difference from spec, also hash with charcount
                hash = ((hash >> 14) & 0x01) | ((hash << 1) & 0x7fff);
                hash ^= passwordCharacters.Length;
                hash ^= (0x8000 | ('N' << 8) | 'K');
            }

            return Convert.ToString(hash, 16).ToUpperInvariant();
        }

Answer 2

Okay, so not entirely what I wanted to do, but I ended up dropping Open XML SDK and using Office.Interop assemblies to protect the document. Reason for using Open XML in the first place, was because it seems that an Interop workbook cannot be opened with a stream, it requires an actual file.

Answer 3

You can try this:

using (SpreadsheetDocument spreadsheet = SpreadsheetDocument.Open(mem, true))
{
     foreach (var worksheetPart in spreadsheet.WorkbookPart.WorksheetParts)
     {
          SheetProtection sheetProt = new SheetProtection() { Sheet = true, Objects = true, Scenarios = true, Password = "test" };
          worksheetPart.Worksheet.InsertAfter(sheetProt, worksheetPart.Worksheet.Descendants<SheetData>().LastOrDefault());
     }
}

Answer 4

Con openXml es imposible pero existe utra libreria (Libre) tambien llamada EEPlues o (OfficeOpenXml) esta permite proteger con contraseña nuestro documento de excel sin necesidad de tener instalado Excel en la maquina. a diferencia de openxml no solo lo proteje de edición de archivo si no que tampoco deja abrir el archivo hasta que se le proporcione la Contraseña.

ejemplo de un pequeño proyecto de prueba con OfficeOpenXml:

using OfficeOpenXml;
using System.IO;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a new ExcelPackage
            using (ExcelPackage excelPackage = new ExcelPackage())
            {
                //Set some properties of the Excel document
                excelPackage.Workbook.Properties.Author = "VDWWD";
                excelPackage.Workbook.Properties.Title = "Title of Document";
                excelPackage.Workbook.Properties.Subject = "EPPlus demo export data";


                //Create the WorkSheet
                ExcelWorksheet worksheet = excelPackage.Workbook.Worksheets.Add("Sheet 1");

                //Add some text to cell A1
                worksheet.Cells["A1"].Value = "My first EPPlus spreadsheet!";
                //You could also use [line, column] notation:
                worksheet.Cells[1, 2].Value = "This is cell B1!";

                //Save your file
                FileInfo fi = new FileInfo(@"D:\PruebasXMLS\File.xlsx");
                excelPackage.SaveAs(fi, "123456789");
            }
        }
    }
}

REF: https://riptutorial.com/epplus