I’ve been taking the Cryptography class on Coursera recently, taught by Dan Boneh. It’s terrific… just difficult enough to be a fulfilling challenge, but easy enough that I haven’t churned (yet).
We recently studied a practical application of the Cipher Block encryption methodology called Cipher Block Chaining (CBC). Here’s a diagram from Quora that articulates how CBC works:
It immediately reminded me of the bitcoin blockchain diagram from Santoshi’s original bitcoin white paper:
The key relation in both images that the output cipher from each round of encryption is fed into the input of the encryption of the subsequent round, to create a chain. It’s very elegant. I never knew the origin of this structure before… and I’m sure its roots go back beyond CBC.
I love moments of abstraction connection like this… this is why I take Coursera classes. They’re very academic, which doesn’t seem useful at first, but I find they make me look at my day-to-day interactions through a new lens, which spurs serendipitous moments of creative connections I would otherwise miss.