How to password protect an excel file through Matlab?

I am trying to password protect an Excel file which is created using Matlab..

clc;clear;dFlag_Excel = 0;
xlsfile = 'Try_V1.xlsx';
password = 'Test';
Excel = actxserver('Excel.Application'); % open Excel as a COM Automation server
Workbooks = Excel.Workbooks;
Workbook = Workbooks.Open([pwd,'\',xlsfile]);
Workbook.Protect(password, 'True', 'True');

But I am getting an error in this last line above in the script:

??? Invoke Error, Dispatch Exception: The parameter is incorrect.

Error in ==> Untitled at 7

Workbook.Protect('Test@123', 'True', 'True')

[Ehtisham]

https://www.mathworks.com/matlabcentral/fileexchange/94983-xlsprotect-password-protect-excel-files-through-matlab

Go to the above link and download the simple code. It is easy to use and I have created it myself because I was facing the same problem as you and the code provided by anyone else did not serve my purpose. So I created the code myself.

Answer 1

[Image Analyst]

Have you checked out the Excel API for workbooks and worksheets: https://docs.microsoft.com/en-us/office/vba/api/Excel.Worksheet.Protect

From what I can see from the left panel, the worksheet object has a Protect() method but a workbook object does not. However, the text is ambiguous. It says

A string that specifies a case-sensitive password for the worksheet or workbook. If this argument is omitted, you can unprotect the worksheet or workbook without using a password. Otherwise, you must specify the password to unprotect the worksheet or workbook. If you forget the password, you cannot unprotect the worksheet or workbook.

Yet up at the top, and in the left panel it seems to say only worksheets, not workbooks. Perhaps it means that if a workbook has only one worksheet then protecting the worksheet will also protect the workbook, however it doesn't say that explicitly. If I get time, I'll play around with it later.

[Roofus Milton]

'works fine on my machine'

excel = actxGetRunningServer('Excel.Application');

excel.Visible = true;

wb = excel.Workbooks.Add();

wb.Protect("TestPassword", true, true);

[Partha Mitra]

HI Milton,

I really regret the workbook was protected but I could not realise.

But what I needed was not this.

I needed the matlab code using which I protect an excel file using password i.e. when you try to open the excel file or double click the excel file, first you get a pop-up for Password and when you provide the right password then only the contents of the excel file are visible.

Manually for an excel file is done like this:

[Image Analyst]

What does this mean: "I really regret the workbook was protected but I could not realise."? You don't realize/understand what?

You say "I needed the matlab code using which I protect an excel file using password i.e. when you try to open the excel file or double click the excel file, first you get a pop-up for Password and when you provide the right password then only the contents of the excel file are visible." and this is exactly what happens. You save it with the password in that MATLAB script, and when you try to open the Excel workbook, it asks you for that same password before it will open it and show it to you, just like you said you wanted. So I'm baffled as to why you don't just say "Thanks - it works perfectly. Just what I wanted!"

[Partha Mitra]

Hi Image Analyst,

When I try using the code I am only able to protect the workbook (Worksheet names).

Because when i open the excel file, it opens and only when I try to change the worksheet names then I can't do as the workbook is protected.

What I said earlier: I want the excel file protected i.e. when i or anyone tries to open then it asks first for the password. On correct password then it will open the file and show the contents.

I will give a brief flow as of now and then I will give the snapshot what is required:

A. Current work:

Step 0: The excel file without any password:

Step 1: I run the following code in matlab:

clc;clear;dFlag_Excel = 0;
xlsfile = 'ExcelFile_V4.xlsx';
Excel = actxserver('Excel.Application'); % open Excel as a COM Automation server
Workbooks = Excel.Workbooks;
try
Workbook = Workbooks.Open([pwd,'\',xlsfile]);
catch
    Workbooks.Close; % close the workbook
    Excel.Quit;      % quit Excel
    % or invoke(Excel,'Quit');
    delete(Excel);
    dFlag_Excel = 1;
end
try
Workbook.Protect('Test@123', true, true)
% Excel.ActiveWorkbook.Protect('Test@123', true, true);
catch
    Workbooks.Close; % close the workbook
    Excel.Quit;      % quit Excel
    delete(Excel);
    dFlag_Excel = 1;
end

if (dFlag_Excel == 0)
    Workbook.Save;
    Workbooks.Close; % close the workbook
    Excel.Quit;      % quit Excel
    delete(Excel);
end

Step 2: I see the excel file as modified for protection.

2.a. I open the excel file: I can open the file but you can see in below snapshot that the name of the worksheet is protected by password. I also will show the snapshot:

Step 3: Also I can see and modify the contents. Please refer below screenshot:

B. But this is not what I want.

What I want is as showed in my earlier comment as well as now: (I am doing it manually in excel)

New excel file: ExcelFile_V5.xlsx

Step i. Manually I encrypt the excel file using a password.

Step ii. After I set the password as per Step i, I try to open the excel file and I see as below:

This is exactly I want my code to do, but unfortunately it is as per Step 2. and Step 3.

So, please help me to achieve the above as per Step ii

[Image Analyst]

Try this:

dFlag_Excel = 0;
xlsfile = 'ExcelFile_V4.xlsx';
Excel = actxserver('Excel.Application'); % open Excel as a COM Automation server
Workbooks = Excel.Workbooks;
try
	Workbook = Workbooks.Open([pwd,'\',xlsfile]);
catch
	Workbooks.Close; % close the workbook
	Excel.Quit;      % quit Excel
	% or invoke(Excel,'Quit');
	delete(Excel);
	dFlag_Excel = 1;
end
try
	% Define the password for the workbook and the worksheet, BOTH.
	workbookPassword = 'Test@123wb';
	worksheetPassword = 'Test@123'; % Could be different from the workbook password if you want.
	% Set the password property for the Workbook.
	Workbook.Password = workbookPassword;
	% Now protect the sheet inside the workbook, if there are multiple worksheets.
	% Otherwise if there is only one sheet, the workbook password will open the worksheet also.
	Workbook.Protect(worksheetPassword, true, true)
	% Excel.ActiveWorkbook.Protect('Test@123', true, true);
catch
	Workbooks.Close; % close the workbook
	Excel.Quit;      % quit Excel
	delete(Excel);
	dFlag_Excel = 1;
end
if (dFlag_Excel == 0)
	Workbook.Save;
	Workbooks.Close; % close the workbook
	Excel.Quit;      % quit Excel
	delete(Excel);
end

[Partha Mitra]

Thanks for your help! it works perfectly.

[Partha Mitra]

Thanks Image Analyst and thanks Milton!

[Roofus Milton]

Here are the steps to cycle through protected states.

Local Variables

existingFilePath = "C:\*********.xlsx";
filePath = "C:\*********.xlsx";

openPassword = "OpenPassword";
wbProtectPassword = "Workbook";
wsProtectPassword = "Worksheet";

Create Excel Objects

% attach to open Excel instance
excel = actxGetRunningServer('Excel.Application');

% ensure Excel is visible
excel.Visible = true;

% check to see if we create a new workbook or open existing
if(strcmp(existingFilePath, ""))
    
    % add a new workbook to the workbooks collection
    wb = excel.Workbooks.Add();

else

    % open existing file, note [] facilitates optional parameters
    wb = excel.Workbooks.Open(existingFilePath, [], [], [], openPassword);
    
end

% set the active worksheet
ws = wb.ActiveSheet();

Workbook

Protect the Workbook

% protect the sheet
wb.Protect(wbProtectPassword, true, true);

% set the password property
wb.Password = openPassword;

Test Workbook Protection

If ProtectStructure returns a logical 1, the code below will produce an error: "Add method of Sheets class failed".

% check if the workbook structure is protected
wb.ProtectStructure

% add a worksheet to the workbook
ws2 = wb.Sheets.Add();

% rename the worksheet
ws2.Name = "TestSheet";

Unprotect the Workbook

% set the password to an empty string removes password requirement
wb.Password = "";

% unprotects the workbook structure
wb.Unprotect(wbProtectPassword);

Worksheet

Protect the Worksheet

% check to see if we created a new workbook, only write data if we create a
% new workbook
if(strcmp(existingFilePath, ""))

    % write test data
    ws.Range("A1").Value2 = "Roofus";
    ws.Range("B1").Value2 = "Milton";
    ws.Range("C1").Value2 = "Bear";

end

% set worksheet level protection
ws.Protect(wsProtectPassword, true, true);

Test Worksheet protection

If the ProtectContents property returns a logical 1 then the code will produce an error.

% get the protected status
ws.ProtectContents

% write test data
ws.Range("A2").Value2 = "Test1";

Unprotect the Worksheet

% call the unprotect method
ws.Unprotect(wsProtectPassword);

% write test data
ws.Range("B2").Value2 = "Test2";

Cleanup

% save the file
wb.SaveAs(filePath);

% close the file
wb.Close();

Answer 2

[Nicolas B.]

I recommand you to use the xls_protect_sheets() from MATLAB exchange. It will be easier for you.

[Partha Mitra]

This works but it only protects the sheet.

What I want is to protect the file completely.

I don't want others to open the file without a password.

[Ehtisham]

https://www.mathworks.com/matlabcentral/fileexchange/94983-xlsprotect-password-protect-excel-files-through-matlab

Go to the above link and download the simple code. It is easy to use and I have created it myself because I was facing the same problem as you and the code provided by anyone else did not serve my purpose. So I created the code myself.

Answer 3

[Roofus Milton]

You are passing 'True' as a char when it should be logical/boolean.

Workbook.Protect('Test@123', true, true)

[Partha Mitra]

Hi Milton,

I tried as per your suggestion but the excel file is still unprotected.

I tried using 2 ways :

1. As suggested by you:

Workbook.Protect('Test@123', true, true)

2. Excel.ActiveWorkbook.Protect('Test@123', true, true);

There is no popup for any error in MATLAB. But also the excel file remains unprotected.

Am I missing some settings which I need to do?

[Roofus Milton]

Your previous comment indicated the error moved from line 7 to line 18. I don't have your code so I am not sure what would contribute to the new error.

The code below sets the Password property of the workbook. This is separate from the Protect method.

filePath = "C:\Users\************.xlsx"

openPassword = "OpenPassword";
protectPassword = "ProtectPassword";

% attach to open Excel instance
excel = actxGetRunningServer('Excel.Application');

% ensure Excel is visible
excel.Visible = true;

% add a new workbook to the workbooks collection
wb = excel.Workbooks.Add();

% set the password property
wb.Password = openPassword;

% set ws variable to the active worksheet in wb
ws = wb.ActiveSheet();

% test data
ws.Range("A1").Value2 = "Roofus";
ws.Range("B1").Value2 = "Milton";
ws.Range("C1").Value2 = "Bear";

% protect the sheet
wb.Protect(protectPassword, true, true);

% save the file
wb.SaveAs(filePath);

% close the file
wb.Close();

[Image Analyst]

This code works for me. It does ask for the password upon reopening the file from disk.

[Ehtisham]

https://www.mathworks.com/matlabcentral/fileexchange/94983-xlsprotect-password-protect-excel-files-through-matlab

Go to the above link and download the simple code. It is easy to use and I have created it myself because I was facing the same problem as you and the code provided by anyone else did not serve my purpose. So I created the code myself.