Check if Digital Signature of VBA Code is Valid

Aspose.Cells allows you to check if the digital signature of the VBA code is valid using the Workbook.VbaProject.IsValidSigned property. It will return true if the signature is valid otherwise it will return false. The digital signature of the VBA code becomes invalid when you change the VBA code.

Check if Digital Signature of VBA Code is Valid in C#

The following code demonstrates the usage of this property using the sample excel file which you can download from the provided link. The same excel file has a valid signature but when we modify its VBA code and save the workbook and then recheck, we find its signature has become invalid.

// For complete examples and data files, please go to https://github.com/aspose-cells/Aspose.Cells-for-.NET
// The path to the documents directory.
string dataDir = RunExamples.GetDataDir(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

Workbook workbook = new Workbook(dataDir + "sampleVBAProjectSigned.xlsm");

// Signature is valid
Console.WriteLine("Is VBA Code Project Valid Signed: " + workbook.VbaProject.IsValidSigned);

// Modify the VBA Code, save the workbook then reload
// VBA Code Signature will now be invalid
string code = workbook.VbaProject.Modules[1].Codes;
code = code.Replace("Welcome to Aspose", "Welcome to Aspose.Cells");
workbook.VbaProject.Modules[1].Codes = code;

// Save
workbook.Save(dataDir + "output_out.xlsm");

// Reload
workbook = new Workbook(dataDir + "output_out.xlsm");

// Now the signature is invalid
Console.WriteLine("Is VBA Code Project Valid Signed: " + workbook.VbaProject.IsValidSigned);