In this chapter, we will discuss the advanced concepts of blockchain and the various protocols, challenges, and solutions to it. In the earlier chapters, we looked at the consensus protocol or algorithm as one of the most critical components, or building blocks, of the blockchain. When we speak about blockchain, the first thing that comes to mind is security and the blockchain consensus algorithm. We will look into these challenges and the solutions. From there, we will progress into smart contracts and how they work with the protocols in the blockchain.

In this chapter, we will cover the following advanced concepts of the blockchain:

• Consensus protocols, which are the running engine of the blockchain
• Types of consensus algorithms
• Key challenges in the blockchain to maintain privacy
• Smart contracts
• Distributed applications