I have a few Excel documents we need to sign at my job. Also some PDF ones. I've looked everywhere and all sites shows an "easy" answer but all lead to the same: obtain a digital id from microsoft. On their site they say "if you don't want to buy a certificate from a CA..." Well, we have one in a P12 format but I can't find a way to use it in Excel. The so called "signature line" forces you to get a microsoft id.
We signed the PDF files with FoxIt, which allows you to select a P12 file for signing the document. Anything like that on Excel?
By the way, which CA offers certificates for code signing?
Edit: Maybe the P12 file has to be installed in the certificate store, but I don't know whether it has to be local or personal, and in which part of the store should it appear. Maybe that's the reason that Excell asks to obtaing a digital id since it can't locate a certificate