I think this kind of explanation is brilliant. One on public-key cryptography would be really good but i'm not sure where to start.

I just want to thank you for doing these. We teach the basics of stuff like password security (and while I find security fascinating it's really not my area of expertise) and this will be great for our kids to help them understand (the bit on salting certainly helped me!).

A similar explanation for bitcoin would be great.

I loved this series thanks for writing it.