Yes, you are well on your way to understanding. In the most simple definition blockchain is a technology, a software protocol in which many computers can communicate and agree on information, putting it into blocks on a blockchain. A cryptocurrency is a digital asset that uses blockchain as its underlying technology to exist. In regard to your questions about approval, I believe governments are beginning to accept it and find a way to regulate bitcoin and other cryptocurrencies so that they can be used as legal forms of payment. We will see....