Digital Signatures

When a digital signature is attached to a file it prevents any unauthorised changes to the file because the digital signature is overwritten when the file is saved.

Do I need a Digital Signature ?

If you are an in-house developer or are responsible for maintaining and distributing macros to several people then it may be worth getting a digital signature.
This will allow you to quickly identify if any of the workbooks, documents, templates or add-ins have been tampered with.
When the macro security is set to High any unsigned macros will be automatically disabled.
For more information about the different levels of macro security, please refer to the Macro Settings page.