During this initial week we will start by looking at how the blockchain data are shared among nodes in the peer-to-peer network over the internet and how the interconnectivity of the nodes is managed.

We will continue to look more closely at how nodes add blocks to the data structure with the goal of maintaining a consistent transaction history. We’ll also see that multiple histories can sometimes arise due to a variety of factors ranging from benign, but unpredictable, node outages to intentional malfeasance. This requires that the system have a means of collectively determining which single history is the correct one. We’ll explore two approaches to achieve this: the longest chain criterion and the heaviest chain criterion and practice applying the principles that we have learned in this week’s assignment.

The blockchain is not a perfect system and indeed has its limitations. We will explore some of the constraints of the blockchain and address the issues that cause such limitations.