Basically, blockchain ledger contains continous lists of records which are secured by the methods of cryptography. These lists of records are called blocks. It is called blockchain because every block has a link to the previous block. That’s how blocks come in chains.
Blockchain data cannot be altered so it is open and private ledger that holds information of previous transactions between two parties involved. It works through the peer-to-peer network that has protocols for validation of the new blocks.
If one intends to change data contained in the blockchain, it has to change the entire blockchain. For alterification of that size, it is needed consent of everyone involved in the blockchain. Besides being a valid security measure it is a great way of democratic decision-making about the project’s future.
Blockchain technology is one of the great intrinsic values of the Bitcoin. Bitcoin’s core was the blockchain ledger published by Satoshi Nakamoto back in 2008. It was the first implementation of the blockchain technology. That way, great issue of digital currency was resolved. That issue is called “double-spending”. Basically, it is all about the possibility of spending one token more than one time. Besides obvious problem, double-spending leads to the inflation of the currency. Useful methods against it are blind signatures and secret splitting. Both used in today’s cryptocurrency.
Blockchain technology managed to resolve all those issues without using any central authority or server.
So, what is the importance, shortly? The fact that digital information through the blockchain ledger is distributed, but not copied.
Besides the original invention through Bitcoin, blockchain technology finds other practical solutions, becoming the foundation of the new Internet societies. Besides transactions, blockchain can record anything else. Ethereum is a platform that uses blockchain in many ways. So, on Ethereum, individualsvcan create programs and applications, and get funded in ether. Economy and technology in one concept.