In light of the success of cryptocurrencies, financial companies have shown a lot of interest to the technology underlying those cryptocurrencies, Blockchain. Digging the subject made me understand that all this “god-like” expectation from this technology is nothing more than a marketing spin and people marketing it as a revolution are making the same mistake a lot of people 2 decades ago did when talking about internet.

Well first, Blockchain is not Bitcoin or Ethereum, and cryptocurrencies are not Blockchain. Blockchain, is nothing than a BASIC distributed network database technology, with the property of being a WRITE ONCE READ ONLY DATABASE SYSTEM. Explained in simple words : It is nothing than a giant excel spreadsheet, shared in internet, where everybody can add content, and nobody can delete this content once written.

This huge sheet has entries that are called in the case of cryptocurrencies, transactions. Each transaction has a sender, a recipient, an input amount, and an output amount, and a potential short message.  This sender and the recipient are given encrypted addresses as pseudonym (Something like that : 87oLugRB1fdvqFC1BHkBwjZWm2wbuio9PM).

Then, why it’s being called blockchain and not huge sheet/database ?

Well, this comes from the process of adding transactions to the database. People can’t just write their transactions in real time. Allowing such thing would be very risky. Instead, for the case of bitcoin for instance, some computers in the bitcoin network called miners, listen for new transactions in the P2P network, bundle a bunch of transactions in a list/bloc, and compute with other computing power to add the bundle/block in the network, thus creating another chain with this block. This is why we call it blockchain.