I've been looking into this whole area recently for a project. The problem isn't (only) the technical issues. As TFA points out, this is easy, and even the mos

I've been looking into this whole area recently for a project. The problem isn't (only) the technical issues. As TFA points out, this is easy, and even the most naive and simplistic implementation beats physical signatures hands-down. There's two main problems: 1. Legality. Getting a court to recognise a digital signature probably isn't that hard. It's a bit like scanned images - if you can prove that this is the best evidence, then it'll probably be accepted. However, getting lawyers to accept digital signatures is difficult. One of those awkward situations where there's no consequences for them if they insist on a physical signature but lots of potential downside should they accept a digital signature. 2. File formats, or "the standards problem". To include a digitial signature in a document, we need a file format that includes digital signatures. Every document file format has a different version of this, and every digital signature service provides a different "wrapper" format with a different signature. This needs to be solved top-down. The SCOTUS, or the EU Court, or some organisation of similar standing, needs to say "this wrapper format is the only type of signature legally accepted, and if a document is wrapped in this format, it is legally signed". Both problems vanish and we can have nice things again.