I just read this:
The problem is that if there is a dispute over what was actually in the NDA later on, its going to be extremely difficult to establish what the NDA said. I'd refuse to sign an online NDA out of fear that some years from now, I'd be presented with "you signed this document" which looks nothing like the document I thought I signed.
I think this is applicable to both online and hardcopy documents in the same way. For hardcopy, someone with enough sophistication could just either copy your signature, or graft it from one document to another. Likewise, for electronic media, you could easily just paste their electronic signature onto a different document, since it's just bits of 1's and 0's that the document is saved in the database or cloud with, so it's easily changed.
I'm wondering how you can prevent these problems. If you are the one creating the document to be signed, wondering what must need to be done so that if you were in court the document would be considered valid, the content considered the original content and valid, and the signature considered valid. If you give a copy of the document to the person signing it, then they could use it to reference the original. But if they lose it, then they lose the protection. Also, they could just throw it away and say that they never got a copy, and say that you changed the original contract. I'm not sure how one would protect against this sort of stuff, what needs to be done on the document creator's part to maintain "legal validity" or "legal soundness". Seems like documenting the process somehow might help, but I can see loopholes there as well. Hoping one could outline/clarify what should be done here.