This module introduces consensus algorithms and discusses the security of the most common variants. Consensus algorithms are essential to a distributed, decentralized ledger, where a network of nodes must agree on an official version of the ledger without a central authority. This course describes the underlying principles of consensus algorithms, how two of the primary consensus algorithms work under the hood and how they can be attacked.

This module discusses the ecosystem where the blockchain runs (the nodes and network) and its security. After understanding the different components of the blockchain, it is possible to discuss its security as a whole. This course investigates how blocks are created in the blockchain (and how block creation can be attacked) as well as discussing attacks targeting blockchain nodes and the network that ties them together and enables communication.

This module introduces smart contracts and discusses some of the most common programming errors made in smart contract development. Smart contract platforms are an extension of the original blockchain design, enabling fully functional programs to run “on the blockchain.” This course describes what a smart contract is and explores programming vulnerabilities that exist because a smart contract is a program, runs on a blockchain or is implemented on the Ethereum smart contract platform.

This module goes beyond the basic blockchain to discuss other distributed ledger architectures, advanced cryptographic protections, and blockchain extensions like sidechains and second-layer protocols. It discusses how the blockchain protocol can be replaced (using different underlying architectures), expanded (with second-layer protocols) or improved (using advanced cryptographic primitives) to overcome some of the limitations of blockchain technology.