Blockchains

This chapter focuses on the details of blockchainsBlockchains. The characteristics of blockchains are introduced in the first section and in the second section the environmental influence of cryptocurrencies is described, which is based on a report from the Columbia Climate School. The second section emphasizes on the needs for much more efficient blockchain technologies. In the third section, important blockchain attacks are introduced, which include attacks on Nxt, Decentralized Autonomous Organization (DAO), and Binance. For the case of the DAO, issues regarding compensation, delistings, as well as the U.S. Securities and Exchange Commission (SEC) rulings and Simple Agreement for Future Tokens (SAFT) investment contract information are provided. In the fourth section, a comparison of Bitcoin and Ethereum is provided. In the fifth section, details of the Byzantine Fault Tolerance (BFT) consensus mechanism are introduced, including the BFT operation and examples of the Byzantine Generals problem. The details of Chap. 8 are abundantly used in Chap. 9 (titled “Bitcoin”) and Chap. 10 (titled “Smart Contracts & Ethereum”).