What Even Is a Blockchain?
Blockchains are all the rage these days. The most popular implementation is Bitcoin, which is a speculative bubble that also in theory operates as a currency, though in practice it's extremely difficult to use. There are many aspects of Bitcoin that are technically interesting and the way it combines various concepts and technologies is rather novel. The original whitepaper is eminently readable if you want to know more. What I want to know is about the underlying blockchain technology. How does it work? What practical applications does it have? Is there a use for it—or a lesson we can learn from it—that we can apply to more practical problems?
First, we need to know what problem it solves. At its core, a the blockchain concept described in the Bitcoin whitepaper serves as an immutable trustworthy ledger.