I don't think you need to explain cryptocurrency from the technical point of view. Just like we explain the internet: it is an information protocol. We did not explain about TCP/IP and IP v4 stuff. Just mention that it is a digital currency where money can be transferred quickly with a reasonable fee. And then show the wallet, how to transfer, and stuff...
Cryptocurrency is hard to understand if you are a computer illiterate, understand the concept of bitcoin, I think you must understand the computer first. After that you can proceed to what is bitcoin, so that you can understand it slowly but clearly.