How can we open password protected excel file with npoi?

[karanjshah]

If anyone can guide me that how can we access password protected file with NPOI in c# then it would really very grateful for me.

Thank You

[Bykiev]

@karanjshah, hi

you can use this code from the [NPOI.TestCases] project (https://github.com/tonyqus/npoi/blob/master/testcases/main/POIFS/Crypt/TestDecryptor.cs):

POIFSFileSystem fs = new POIFSFileSystem(new FileStream("protect.xlsx", FileMode.Open));
EncryptionInfo info = new EncryptionInfo(fs);
Decryptor d = Decryptor.GetInstance(info);
d.VerifyPassword("password");

But this code is not working, because NPOI.POIFS.Crypt namespace is missing (Crypt folder is excluded from the project) for some reason...

@tonyqus, can you confirm it was excluded by mistake?

[afrikaan-official]

any update on this ?

[avoll]

Would love to hear an update!

[jlgordo]

Hello @tonyqus , do you have an estimated date to have this issue solved?

[niikoo]

+1

[daveechols]

I would like to see an update/timeline on this also. I am trying to open an Excel 2016 password protected file but I get errors.

this is the error I get....

System.IO.IOException
HResult=0x80131620
Message=Not found type NPOI.POIFS.Crypt.Agile.AgileEncryptionInfoBuilder
Source=NPOI
StackTrace:
at NPOI.POIFS.Crypt.EncryptionInfo..ctor(ILittleEndianInput dis, Boolean isCryptoAPI)
at NPOI.POIFS.Crypt.EncryptionInfo..ctor(POIFSFileSystem fs)
at Test_NPOI_Password.Program.Main(String[] args) in C:_Projects\Research\General\Test_NPOI_Password\Program.cs:line 20

This exception was originally thrown at this call stack:
[External Code]

I

This is the code I used...

  POIFSFileSystem fs = new POIFSFileSystem(new FileStream("Book1.xlsx", FileMode.Open));
  EncryptionInfo info = new EncryptionInfo(fs);
  Decryptor d = Decryptor.GetInstance(info);
  d.VerifyPassword("admin123");

Book1.xlsx

[rajnishdubey3]

Hello,

Is there any fix for this. I would like to open and read a Password protected Excel file on the server-side.

I used the below code.

`

Public Sub open_2()

    Dim fp As String = "C:\Desktop\Test\Filewithpassword\File with pass_2.xlsx"
    Try
        Dim nfs As NPOI.POIFS.FileSystem.POIFSFileSystem = New NPOI.POIFS.FileSystem.POIFSFileSystem(New FileStream(fp, FileMode.Open, FileAccess.ReadWrite))
        Dim password As String = "12345"
        Dim info As EncryptionInfo = New EncryptionInfo(nfs)
        Dim dc As Decryptor = Decryptor.GetInstance(info)
        Dim b As Boolean = dc.VerifyPassword(password)

        If b Then
            Console.WriteLine("Authenticated.")
        Else
            Console.WriteLine("Wrong password.")
        End If

        Dim excelData As Stream = dc.GetDataStream(nfs)

    Catch ex As Exception

    End Try
End Sub

`

[cbloechle]

+1 Would like to have this feature in our toolbelt.

[tonyqus]

@Bykiev NPOI.POIFS.Crypt is included but I notice that there are a few methods in this namespace, which are not implemented

[AkanshaKumari]

is there any update on this because I have been facing this issue since very long and I need a fix urgently. Else i will have to use other library.

[dp250195]

I noticed that, some files, even if they are password-protected, can still be open with Excel without an issue. These files have only their structure protected, but contents can still be read.

Is it possible to open such files in read-only mode, without specifying a password and without triggering an exception?

[tim-rue]

I found this PR just after creating a workaround myself. I tested it and I can confirm #883 works like a charm!

[tonyqus]

I'm testing code of #883. Looks it's not fully working. @tim-ruecker can you give me a sample code that is working on your side?

Exception I got:
NPOI.EncryptedDocumentException:“Export Restrictions in place - please install JCE Unlimited Strength Jurisdiction Policy files”

[tim-rue]

@tonyqus This exception is commented out in #883:

npoi/main/POIFS/Crypt/CryptoFunctions.cs

Lines 212 to 214 in b5f9afd

	/*if (Cipher.GetMaxAllowedKeyLength(cipherAlgorithm.jceId) < keySizeInBytes * 8) {
	throw new EncryptedDocumentException("Export Restrictions in place - please install JCE Unlimited Strength Jurisdiction Policy files");
	}*/

Are you sure you checked out the right branch?

This is how I open the workbook:

POIFSFileSystem fs = new POIFSFileSystem(new FileStream(@"path\to\excel.xlsm", FileMode.Open));
EncryptionInfo info = new EncryptionInfo(fs);
Decryptor d = Decryptor.GetInstance(info);

var validPassword = d.VerifyPassword("password");
if(!validPassword)
   return; //todo throw exception

var st = d.GetDataStream(fs);
var xssWorkbook = new XSSFWorkbook(st);

[tonyqus]

My bad. I used the wrong branch. Looks it works very well.

[tim-rue]

@tonyqus Great. Any chance we can have this added to 2.6.0?

[dontbyte]

Great, huge big thanks to all of you! @KnyazSh @tonyqus @tim-ruecker

[tonyqus]

@tim-ruecker #883 will be shipped with 2.6.0. I've merged the PR.

[JulienLeal]

How can I encrypt the xlsx? With this way I only can decrypt the file, right? @tonyqus

[tonyqus]

@JulienLeal It's not supported.

[egtalbot]

I have 2.6.0 and trying to open a sheet where the tabs are password protected against changes and this line gives me an error:
POIFSFileSystem fs = new POIFSFileSystem(new FileStream(stream))

Note, I am inside a using statement after opening a stream when I execute that line. Error indicates the supplied data is Office 2007+ XML. It's an xlsx file just like in the example from @tim-rue so not sure what's going wrong.

[tonyqus]

@egtalbot POIFSFileSystem is for xls only.

Please try the following code:
IWorkbook workbook = WorkbookFactory.Create("encryped.xlsx", "password");

[egtalbot]

@egtalbot POIFSFileSystem is for xls only.

Please try the following code: IWorkbook workbook = WorkbookFactory.Create("encryped.xlsx", "password");

Thanks - I did try that and it failed to create. I tried so many things I can't even remember what the error was, but I'm moving back to ExcelDataReader.

I do appreciate the response