In Chapter 8, we overview a number of interesting applications built atop Bitcoin’s blockchain. Namely, we describe Namecoin, the first clone of Bitcoin, which implements a decentralized Domain Name Service for registering Web addresses that end in “.bit,” and which is resilient to censorship. We then overview Litecoin and Dogecoin, two of the most known altcoins derived from Bitcoin. We also discuss other applications of the Bitcoin blockchain, such as decentralized and authenticated storage and smart contracts. We additionally show how Bitcoin can be used to instantiate a decentralized time-dependent randomness generator. Finally, we discuss current efforts to repurpose the proof-of-work of Bitcoin toward useful computations, among other proposals by digital assets and sidechains to extend the basic functionality of Bitcoin.
In Chapter 9, we overview a number of interesting blockchain proposals that are currently competing with Bitcoin. These proposals have been mainly motivated by the success of Bitcoin and attempt to solve some of the caveats encountered in the Bitcoin system.
Namely, we describe Ripple, Ethereum, and the IBM Open BlockChain technologies. We compare these blockchains to Bitcoin with respect to their security and privacy provisions.
Finally, in Chapter 10, we summarize the main lessons learned from the previous chapters. Namely, we summarize the security and privacy provisions of Bitcoin, and its underlying blockchain—effectively capturing 8 years of thorough research on these subjects. In addition to discussing existing vulnerabilities of Bitcoin and its various related altcoins, we also summarize possible countermeasures to deter threats and information leakage within the system.
As far as we are aware, this book offers the most comprehensive and detailed analysis of the security and privacy provisions of Bitcoin and of its related clones/variants. We hope that the contents of the book provide the necessary tools and building blocks for the design of secure next-generation blockchain technologies.