Cannot save presentation without removing digital signatures

[Guest]

I have a presentation with VBA code that I created on my home computer along
with the necessary "self certification" necessary to allow it to run the next
time I open it.

I have since copied this presentation to my work laptop, and following the
same steps I used at home, I was able to get it to run the VBA code.
However, when I try to save the presentation, I get the message, "This
presentation contains digital signatures. Saving the presentation removes
all existing signatures."

Then, true to its word, if I continue with the save, the digital signatures
are removed. If I reopen the presentation, I need to add the digital
signatures back in before the VBA code will run.

How can I get the presentation to save without removing digital signatures?

 

[Guest]

Just as an addendum, I have a second presentation with similar VBA code that
I was able to transfer to my laptop and had it working fine. So the problem
seems to be specific to the other file.

 

[Steve Rindsberg]

I have a presentation with VBA code that I created on my home computer along
with the necessary "self certification" necessary to allow it to run the next
time I open it.

I have since copied this presentation to my work laptop, and following the
same steps I used at home, I was able to get it to run the VBA code.
However, when I try to save the presentation, I get the message, "This
presentation contains digital signatures. Saving the presentation removes
all existing signatures."

Then, true to its word, if I continue with the save, the digital signatures
are removed. If I reopen the presentation, I need to add the digital
signatures back in before the VBA code will run.

How can I get the presentation to save without removing digital signatures?

I'm certainly no expert on sigs, but here's my guess:

If you could do what you want, there'd be no point in having the signature in
the first place.

The signature is specific to a particular computer; in effect, it testifies that
the code hasn't been changed since it left the computer and it ties the computer
to you.

When I choose to run digitally signed code, I have no idea whether it's
malicious or not, but I'm at least fairly sure I know who made it and where to
find him if it does bad things to my computer.

The whole point, then, is that if anyone other than you on your own PC alters
the code in any way and resaves it, the signature goes away.

You'd have to resave it from the original PC or re-sign it on the other PC.