Spectre, explained as if computer were banks /img/spectre-and-meltdown.jpg

I just saw on Twitter a thread by Professor Clay Shirky that gives a good, simple explanation of what Spectre is and why it is dangerous (which I believe to be valid, in a broad sense, also for the other big computer threat of the moment, Meltdown (1)). With Prof. Shirky’s permission, I reformatted the whole thread and now publish it here, so that it is fully readable, and useful, even outside Twitter (emphasis in the text below is mine)