Blockchain is a decentralized, digital ledger that records transactions and keeps track of digital assets or assets’ ownership. It was first introduced as a technology for Bitcoin, the world’s first cryptocurrency and blockchain. Over time, people discovered that the same technology could be used to record other types of transactions, such as the transfer of digital assets or property ownership. The most popular general purpose blockchain today is Ethereum. It's generally recognized as the most decentralized, secure and with the most developed ecosystem of developers and tools.