You just have to make it hard enough that the likelihood of it being tampered with is small enough to be acceptable for a court. If you're up against the NSA t

You just have to make it hard enough that the likelihood of it being tampered with is small enough to be acceptable for a court. If you're up against the NSA then pretty much any tech evidence would be invalid. But if you're having a small claim court case, then it seems reasonable that authentication technology can keep up with faking technology.