The blockchain is a secure system that allows users to transact among themselves (peer-to-peer) through their computers by trust. This is done without any third party or intermediaries. It uses a code that can be shared and distributed for free to any network without compromising the privacy of the users. If a Smart Contract is employed, this code will execute automatically, when certain conditions are met or not met. The code is usually written in C++. Thus, it is a ledger that contains data.