Blockchain originated in Nakamoto's bitcoin, which is essentially a decentralized repository of bitcoin technology.
Refers to the technical solution of collectively maintaining a reliable database by decentralization and de-trust.
Blockchain technology has the characteristics of: decentralized, openness, independent, security, and anonymity.
Blockchain technology is considered the most disruptive technology innovation since the Internet was invented, it relies on cryptography and mathematics smart decentralized algorithms, on the Internet, where trust can not be established, participants can reach a consensus without the intervention of any third-party center, reliable delivery of trust and value at very low cost.
Cryptocurrency uses cryptography to ensure transaction security and to control the creation of transactional units.
Bitcoin became the first decentralized cryptocurrency in 2009, after which cryptocurrency mostly refers to such designs.
Several similar cryptocurrency have been created since then, and they are often called altcoins.
Cryptocurrency is based on a decentralized consensus mechanism, as opposed to a banking financial system that relies on a centralized regulatory system.
The decentralized nature stems from Blockchain technology that uses decentralized books.
Smart contracts are digital versions of traditional contracts. They are computer programs that run on the blockchain database and can execute on their own when the conditions written in their source code are met.
Smart contract once written can be trusted by the user, the contract terms can not be changed, so the contract can not be changed.
Ethereum project draws on the technology of the Bitcoin blockchain and extends its application. If bitcoin is a specialized calculator that uses blockchain technology, then Ethereum is a general-purpose computer that uses blockchain technology.
Briefly, Ethereum = Blockchain + Smart contract. The biggest difference with bitcoin over Ethereum is that it supports a more powerful scripting language (Turing-complete scripting language in technical languages), allowing developers to develop arbitrary applications on top of any Smart contract, This is also the most powerful reason for Ethereum.