# How to secure communication

Secure communication is everywhere: when using your online bank account, sending an email, or sharing a secret over your favorite chat service. But how does this work? How do you secure your messages? And what happens when quantum computers can break this communication security?

## Further thinking

Suppose you are Eve. How would you try to find out what the contents of the 4-bit message in this video was? How would your answer change if the message was 400 bits? Why do you think encryption with a private key is considered secure?

## Further readings

If you are interested in an expert and rigorous mathematical insight on the subject, take a look at the book "A Mathematical Theory of Communication" by Shannon, C.E. (Bell System Technical Journal, July 1948). One relevant chapter can be found here.