I stumbled on a very easy to understand article that describes how prime numbers (those evenly divisible only by themselves and 1) form the basis for secure computer communications. You’ve seen https:  vs http: in URL’s and probably know the added “s” means secure. Maybe you know that SSL means secure sockets layer, which sends and receives information in an encrypted form. And once in a while you might see a warning that a web site has a problem with its security certificate. Do you know that all this is based on the huge amount computational work needed to factor a large prime number?

Read more here: http://www.extremetech.com/extreme/219570-what-are-prime-numbers-and-why-are-they-so-vital-to-modern-life

The link above explains how all this works, without using any math.