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Why Decrypt Excel Worksheet?
To protect our Excel file data information, we can encrypt Excel worksheet by setting password. But we may sometimes forget the password and we can't read the excel data information neither. So, if this happens we need decrypt Excel worksheet. It’s not easy to decrypt Excel Worksheet which has been encrypted because the reason why we encrypt it is to prevent it from reading by people without password. And now, we do not have password.
How to Use C#/VB.NET to Decrypt Excel Worksheet?
Spire.XLS for .NET, a .NET Excel component which enables .NET applications to fast generate, read, write and modify Excel document without Microsoft Office Excel Automation can help us decrypt Excel worksheet by using C#/VB.NET.
Spire.XLS for .NET presents a very easy solution for developers/programmers decrypting Excel worksheet. We just need sheet.Unprotect( "password" ) method and normal encrypted excel worksheet can be decrypted.
Download Spire.XLS for .NET (or Spire.Office) with .NET framework 2.0 (or above) together. The sample code below will show you how to use C#/VB.NET decrypt Excel worksheet through Spire.XLS for .NET.
using Spire.Xls;
namespace DescryptWorksheet
{
class Program
{
static void Main(string[] args)
{
Workbook workbook = new Workbook();
workbook.LoadFromFile("test.xls");
Worksheet sheet = workbook.Worksheets[0];
sheet.Unprotect("password");
workbook.SaveToFile("result.xls", ExcelVersion.Version97to2003);
}
}
}
Spire.XLS allows users to operate Excel document directly such as save to stream, save as web response, copy, lock/unlock worksheet, set up workbook properties, etc. As a professional .NET Excel component, it owns the ability of inserting content into Excel document, formatting cells and converting Excel documents to popular office file formats. Spire.XLS for .NET supports Excel 97-2003, Excel 2007 and Excel 2010.
When sharing Excel files with other people or sending files out of your organization, you may want to protect sensitive data from being changed, moved, or deleted. The easiest way to prevent accidental or deliberate changes in the contents is to restrict editing on a worksheet or password protect an entire workbook. In this article, you will learn how to protect and unprotect a workbook or a worksheet in C# and VB.NET using Spire.XLS for .NET.
- Password Protect an Entire Workbook
- Protect a Worksheet with a Specific Protection Type
- Allow Users to Edit Ranges in a Protected Worksheet
- Lock Specific Cells in a Worksheet
- Unprotect a Password Protected Worksheet
- Remove or Reset Password of an Encrypted Workbook
Install Spire.XLS for .NET
To begin with, you need to add the DLL files included in the Spire.XLS for .NET package as references in your .NET project. The DLL files can be either downloaded from this link or installed via NuGet.
PM> Install-Package Spire.XLS
Password Protect an Entire Workbook in C# and VB.NET
By encrypting an Excel document with a password, you ensure that only you and authorized individuals can read or edit it. The following are the steps to password protect a workbook using Spire.XLS for .NET.
- Create a Workbook object.
- Load an Excel file using Workbook.LoadFromFile() method.
- Protect the workbook using a password using Workbook.Protect() method.
- Save the workbook to another Excel file using Workbook.SaveToFile() method.
- C#
- VB.NET
using Spire.Xls;
namespace PasswordProtectWorkbook
{
class Program
{
static void Main(string[] args)
{
//Create a Workbook object
Workbook workbook = new Workbook();
//Load an Excel file
workbook.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.xlsx");
//Protect workbook with a password
workbook.Protect("psd-123");
//Save the workbook to another Excel file
workbook.SaveToFile("Encrypted.xlsx", ExcelVersion.Version2016);
}
}
}
Protect a Worksheet with a Specific Protection Type in C# and VB.NET
If you wish to grant people permission to read your Excel document but restrict the types of modifications they are allowed to make on a worksheet, you can protect the worksheet with a specific protection type. The table below lists a variety of pre-defined protection types under the SheetProtectionType enumeration.
| Protection Type | Allow users to |
| Content | Modify or insert content. |
| DeletingColumns | Delete columns. |
| DeletingRows | Delete rows. |
| Filtering | Set filters. |
| FormattingCells | Format cells. |
| FormattingColumns | Format columns. |
| FormattingRows | Format rows. |
| InsertingColumns | Insert columns. |
| InsertingRows | Insert rows. |
| InsertingHyperlinks | Insert hyperlinks . |
| LockedCells | Select locked cells. |
| UnlockedCells | Select unlocked cells. |
| Objects | Modify drawing objects. |
| Scenarios | Modify saved scenarios. |
| Sorting | Sort data. |
| UsingPivotTables | Use pivot table and pivot chart. |
| All | Do any operations listed above on the protected worksheet. |
| None | Do nothing on the protected worksheet. |
The following are the steps to protect a worksheet with a specific protection type using Spire.XLS for .NET.
- Create a Workbook object.
- Load an Excel file using Workbook.LoadFromFile() method.
- Get a specific worksheet through Workbook.Worksheets[index] property.
- Protect the worksheet with a protection type using Worksheet.Protect(string password, SheetProtectionType options) method.
- Save the workbook to another Excel file using Workbook.SaveToFile() method.
- C#
- VB.NET
using Spire.Xls;
namespace ProtectWorksheetWithSpecificProtectionType
{
class Program
{
static void Main(string[] args)
{
//Create a Workbook object
Workbook workbook = new Workbook();
//Load an Excel file
workbook.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.xlsx");
//Get a specific worksheet
Worksheet worksheet = workbook.Worksheets[0];
//Protect the worksheet with the permission password and the specific protect type
worksheet.Protect("psd-permission", SheetProtectionType.None);
//Save the workbook to another Excel file
workbook.SaveToFile("ProtectWorksheet.xlsx", ExcelVersion.Version2016);
}
}
}
Allow Users to Edit Ranges in a Protected Worksheet in C# and VB.NET
In certain cases, you may need to allow users to be able to edit selected ranges in a protected worksheet. The following steps demonstrate how to.
- Create a Workbook object.
- Load an Excel file using Workbook.LoadFromFile() method.
- Get a specific worksheet through Workbook.Worksheets[index] property.
- Specify editable cell ranges using Worksheet.AddAllowEditRange() method.
- Protect the worksheet with a protection type using Worksheet.Protect(string password, SheetProtectionType options) method.
- Save the workbook to another Excel file using Workbook.SaveToFile() method.
- C#
- VB.NET
using Spire.Xls;
namespace AllowEditRanges
{
class Program
{
static void Main(string[] args)
{
//Create a Workbook object
Workbook workbook = new Workbook();
//Load an Excel file
workbook.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.xlsx");
//Get the first worksheet
Worksheet sheet = workbook.Worksheets[0];
//Add ranges that allow editing
sheet.AddAllowEditRange("Range One", sheet.Range["A5:A6"]);
sheet.AddAllowEditRange("Range Two", sheet.Range["A8:B11"]);
//Protect the worksheet with a password and a protection type
sheet.Protect("psd-permission", SheetProtectionType.All);
//Save the workbook to another Excel file
workbook.SaveToFile("AllowEditRange.xlsx", ExcelVersion.Version2016);
}
}
}
Unprotect a Password Protected Worksheet in C# and VB.NET
To remove the protection of a password-protected worksheet, invoke the Worksheet.Unprotect() method and pass in the original password as a parameter. The detailed steps are as follows.
- Create a Workbook object.
- Load an Excel file using Workbook.LoadFromFile() method.
- Get a specific worksheet through Workbook.Worksheets[index] property.
- Remove the protection using Worksheet.Unprotect(string password) method.
- Save the workbook to another Excel file using Workbook.SaveToFile() method.
- C#
- VB.NET
using Spire.Xls;
namespace UnprotectWorksheet
{
class Program
{
static void Main(string[] args)
{
//Create a Workbook object
Workbook workbook = new Workbook();
//Load an Excel file containing protected worksheet
workbook.LoadFromFile(@"C:\Users\Administrator\Desktop\ProtectedWorksheet.xlsx");
//Get the first worksheet
Worksheet sheet = workbook.Worksheets[0];
//Unprotect the worksheet using the specified password
sheet.Unprotect("psd-permission");
//Save the workbook to anther Excel file
workbook.SaveToFile("UnprotectWorksheet.xlsx", ExcelVersion.Version2016);
}
}
}
Remove or Reset Password of an Encrypted Workbook in C# and VB.NET
To remove or reset password of an encrypted workbook, you can use the Workbook.Unprotect() method and the Workbook.Protect() method, respectively. The following steps show you how to load an encrypted Excel document and delete or change the password of it.
- Create a Workbook object.
- Specify the open password through Workbook.OpenPassword property.
- Load the encrypted Excel file using Workbook.LoadFromFile() method.
- Remove the encryption using Workbook.Unprotect() method. Or change the password using Workbook.Protect() method.
- Save the workbook to another Excel file using Workbook.SaveToFile() method.
- C#
- VB.NET
using Spire.Xls;
namespace RemoveOrResetPassword
{
class Program
{
static void Main(string[] args)
{
//Create a Workbook object
Workbook workbook = new Workbook();
//Specify the open password
workbook.OpenPassword = "psd-123";
//Load an encrypted Excel file
workbook.LoadFromFile(@"C:\Users\Administrator\Desktop\Encrypted.xlsx");
//Unprotect workbook
workbook.UnProtect();
//Reset password
//workbook.Protect("newpassword");
//Save the workbook to another Excel file
workbook.SaveToFile("Unprotect.xlsx", ExcelVersion.Version2016);
}
}
}
Apply for a Temporary License
If you'd like to remove the evaluation message from the generated documents, or to get rid of the function limitations, please request a 30-day trial license for yourself.
The most important reason that people lock worksheet when perform tasks in Excel is to protect the original Excel file from editing or modifying by other people. Through Microsoft Excel, you can set the entire Excel worksheet by setting its property as Read Only or just set partial region area cells as Read Only via protecting worksheet. While how to lock worksheet with C#, VB.NET will be the core topic in this section.
Spire.XLS for .NET, as a fast and reliable excel component, enables you to lock your worksheet by setting Worksheet class property: Worksheet.Range.Style.Locked = true. By this component, you can lock any worksheet that you need. In this solution, worksheet one and worksheet two are locked as you view in below picture:
Now, before the detail code, you have to add Spire.Xls dll by download Spire.XLS for .NET.
using Spire.Xls;
namespace lock_excel_worksheet
{
class Program
{
static void Main(string[] args)
{
Workbook workbook = new Workbook();
workbook.LoadFromFile(@"..\lock worksheet.xls");
workbook.Worksheets[0].Range.Style.Locked = true;
workbook.Worksheets[1].Range.Style.Locked = true;
workbook.Worksheets[0].Protect("", SheetProtectionType.All);
workbook.Worksheets[1].Protect("", SheetProtectionType.All);
workbook.SaveToFile("result.xls",ExcelVersion.Version97to2003);
}
}
}
Imports Spire.Xls
Namespace lock_excel_worksheet
Class Program
Private Shared Sub Main(ByVal args() As String)
Dim workbook As Workbook = New Workbook
workbook.LoadFromFile("..\lock worksheet.xls")
workbook.Worksheets(0).Range.Style.Locked = true
workbook.Worksheets(1).Range.Style.Locked = true
workbook.Worksheets(0).Protect("", SheetProtectionType.All)
workbook.Worksheets(1).Protect("", SheetProtectionType.All)
workbook.SaveToFile("result.xls",ExcelVersion.Version97to2003)
End Sub
End Class
End Namespace
Spire.XLS allows user to operate Excel document directly such as save to stream, save as web response, copy, lock/unlock worksheet, set up workbook properties, etc. As a professional .NET/Silverlight Excel component, it owns the ability of inserting content into Excel document, formatting cells and converting Excel documents to popular office file formats. Spire.XLS for .NET supports Excel 97-2003, Excel 2007 and Excel 2010.
