Thanks for your inquiry.
Well, I think Aspose.Cells can suit your needs. Aspose.Cells for .NET library is written in managed C#.NET, so, concurrency and multithreading is not a problem by any means. Our several users do use the component in their diverse environments in different types of solutions (Winforms, web forms, windows/web service, console app. etc.) or scenarios without any problem. Also, Aspose.Cells shows good performance in reading/writing large Excel files.
You may read/write encrypted or protected Excel files, see the documents for your reference:
(see the description/example code under "Opening Encrypted Excel Files" sub-heading)
And, see the documents on how to get worksheets in the workbook by using either its indexed position or by its names:
We recommend you to kindly see the Wiki Conf. Docs and featured demos for your complete reference:
Please do evaluate our product for your scenario. If you find any issue, let us know.