http://carlcheo.com/compsci

A handy list for when talking with your project manager. An example:

Asymmetric cryptography

Sharing identical keys works fine among 2 people. What if Alice want to exchange stuff with another guy named Carl, and Alice doesn’t want anybody to see their stuff too? Alice can’t use the same lock and key that she shared with Bob, else Bob can unlock the box easily!

Of course Alice can share a completely new and different lock and key with Carl, but what if Alice wants to exchange stuff with 10 different people? She will need to keep and manage 10 different keys!

So Alice come out with a brilliant solution. Now, she only maintains one key (private key). She distribute the same padlocks (public key) to her friends. Anyone can close the padlocks (encrypt), but only she has the key to open (decrypt) them. Now, anyone can send stuff to Alice using the padlock she distributed, and Alice no longer have to manage different keys for different people.