Back in July of 2017 I was listening to an episode of the excellent RadioLab series called Breaking News that was covering a phenomenon we now refer to as "deepfakes", or more colloquially, "fake news". That is, news broadcasts that literally contain faked audio clips or doctored video footage.
The implications of this emerging technology are undeniably dangerous. We need only consider how a few internet rumours managed to shape the 2016 US presidential election. Imagine an election held in a world where any candidate can be implicated in a criminal act by way of a doctored video, or perhaps worse, one where a candidate can claim evidence was doctored when it wasn't. Based on my own research, I wasn't able to find any effective response to this problem, so I went about the process of writing one.
I named it Aletheia, after the Greek word for "truth". Basically it's a technical in-the-background-so-you-don't-have-to-be-a-nerd-to-use-it solution to trying to figure out who made the thing you're looking at or listening to. When you publish a thing on your website, be it an audio file, video file, image, or just a web page, a little program runs in the background to sign that thing. Then, as those files float around the web, people (or more likely, other websites) can use that same program to verify the origin of those files.
The name for this technology is public key cryptography and if you're the technical type, you should check out the whitepaper if you're interested. The software is up on PyPi and is AGPL licensed, posted on Github.
Since it's release, I've presented it to PyCon UK in Cardiff 2018, and covered it in a PIR Wired, a podcast from the Department of Politics, International Relations and Philosophy at Royal Holloway, University of London. Both of these are included here.