This talk for beginners will offer a high-level view of how public-key cryptography works, why quantum computing threatens existing public-key cryptography algorithms, and what needs to be done to harden cryptography against quantum attacks.

Users of radio-controlled clocks have discovered that the longwave radio signals that set the time on these devices can be replicated using only a laptop or smartphone and a set of wired headphones or speakers. We'll talk about how this works, why people do it, and a practical example in the C language.