Digital signatures serve as a critical layer of security, ensuring that an Excel file has not been altered since it was signed and verifying the identity of its originator. However, there are scenarios where the detection and removal of these digital signatures become necessary, such as when consolidating multiple documents, updating content, or preparing files for systems that do not support digitally signed documents. This article shows how to detect and remove digital signatures in Excel files with Python code using Spire.XLS for Python, providing a simple way to batch process Excel file digital signatures.

• Detecting the Presence of Digital Signatures in Excel Files
• Removing Digital Signatures from Excel Files

Install Spire.XLS for Python

This scenario requires Spire.XLS for Python and plum-dispatch v1.7.4. They can be easily installed in your Windows through the following pip commands.

pip install Spire.XLS

If you are unsure how to install, please refer to: How to Install Spire.XLS for Python on Windows

Detecting the Presence of Digital Signatures in Excel Files

Spire.XLS for Python provides the Workbook class to deal with Excel files and the Workbook.IsDigitallySigned property to check if an Excel file has digital signatures. Developers can use the Boolean value returned by this property to determine whether the Excel file contains a digital signature.

The detailed steps for detecting if an Excel file has digital signatures are as follows:

• Create an instance of Workbook class.
• Load an Excel file using Workbook.LoadFromFile() method.
• Check whether the workbook is digitally signed by the value of the Workbook.IsDigitallySigned property.

from spire.xls import *

# Create an instance of Workbook
workbook = Workbook()

# Load an Excel file
workbook.LoadFromFile("Sample.xlsx")

# Check whether the workbook is digitally signed
if workbook.IsDigitallySigned is False:
    print("The workbook is not digitally signed.")
else:
    print("The workbook is digitally signed.")

Removing Digital Signatures from Excel Files

Developers can use the Workbook.RemoveAllDigitalSignatures() method to effortlessly delete all digital signatures in an Excel workbook. The detailed steps are as follows:

• Create an instance of Workbook class.
• Load an Excel file using Workbook.LoadFromFile() method.
• Remove all digital signatures from the workbook using Workbook.RemoveAllDigitalSignatures() method.
• Save the workbook using Workbook.SaveToFile() method.

from spire.xls import *

# Create an instance of Workbook
workbook = Workbook()

# Load an Excel file
workbook.LoadFromFile("Sample.xlsx")

# Remove digital signatures
workbook.RemoveAllDigitalSignatures()

# Save the document
workbook.SaveToFile("output/RemoveExcelDigitalSignature.xlsx", FileFormat.Version2016)
workbook.Dispose()

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.