Every Signature Is Broken: Insecurity of Microsoft Office’s Ooxml Signatures
> For documents of prime importance, such as contracts and invoices<p>Few in the legal world actually use cryptographic signatures for signing things. It's vastly more common to use scanned hand signatures or just /s/ and an e-mail record of sign off.<p>Why? Because it has worked that way for hundreds of years. It's pretty uncommon for there to be a dispute about the fact of signature, and even if there is, cryptographic signature solutions don't necessarily solve it.