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Lean Tools, Training, and Systems

Digital Signatures

Understanding digital signatures in Excel documents

As of April 2007, Systems2win began signing each template with a digital signature.

As of mid-January 2010, we discontinued using digital signatures, because they caused too much confusion.

Here's how digital signatures work

As delivered to you — each Excel template was signed with the Systems2win digital signature — and as long as the digital signature remains intact, it gives you the confidence that the macros have been delivered to you as they were when Systems2win signed them.

How digital signatures can be confusing in Excel

As soon as you insert a new worksheet (or click the button to Copy a blank Template worksheet)...

it causes a change to the Visual Basic code, which means that the digital signature can no longer remain valid for that working document, so you get a dialog that says something like: "You have modified a signed project. The signature will be discarded."

What to do when you get a dialog

"You have modified a signed project. The signature will be discarded."

It's no big deal. Just click OK.

Nothing will be affected by the discarded signature. Everything will still work exactly as programmed.

The digital signature has served its purpose — to give you confidence that the code was not tampered with in between the time that Systems2win signed it and when it was delivered to you.

When you first open a workbook

that no longer has a digital signature

You will need to manually enable macros.