The key innovation in Bitcoin, compared to other forms of cryptographic cash (Chaum 1983) or virtual currencies (European Central Bank 2012), is its decentralized core technologies. Early adopters praised decentralization and by all indications chose Bitcoin because they wanted to use a decentralized system (Raskin 2013). Decentralization offers certain advantages. It avoids concentrations of power that could let a single person or organization take control. It often promotes availability and resiliency of a computer system, avoiding a central point of failure.
It offers at least the appearance of greater privacy for users (and perhaps greater genuine privacy) because in theory an eavesdropping adversary cannot observe transactions across the system by targeting any single point or any single server. (However, as we discuss below, significant privacy concerns remain.)
Nonetheless, the decentralization touted by Bitcoin has not fully come to fruition. While the Bitcoin protocol supports complete decentralization (including the possibility of all participants acting as miners), significant economic forces push towards de facto centralization and concentration among a small number of intermediaries at various levels of the Bitcoin ecosystem.
We review four key categories of intermediaries that have shaped Bitcoin’s evolution: currency exchanges, digital wallet services, mixers, and mining pools. A fifth type of intermediary, payment processors, is discussed further below.
Böhme, Rainer, Nicolas Christin, Benjamin Edelman, and Tyler Moore. 2015. "Bitcoin: Economics, Technology, and Governance." Journal of Economic Perspectives, 29 (2): 213-38. American Economic Association
Bitcoin is an online communication protocol that facilitates the use of a virtual currency, including electronic payments. Bitcoin's rules were designed by engineers with no apparent influence from lawyers or regulators.
Bitcoin is built on a transaction log that is distributed across a network of participating computers. It includes mechanisms to reward honest participation, to bootstrap acceptance by early adopters, and to guard against concentrations of power.
Bitcoin's design allows for irreversible transactions, a prescribed path of money creation over time, and a public transaction history. Anyone can create a Bitcoin account, without charge and without any centralized vetting procedure—or even a requirement to provide a real name.
Collectively, these rules yield a system that is understood to be more flexible, more private, and less amenable to regulatory oversight than other forms of payment—though as we discuss, all these benefits face important limits. Bitcoin is of interest to economists as a virtual currency with potential to disrupt existing payment systems and perhaps even monetary systems.
This article presents the platform's design principles and properties for a nontechnical audience; reviews its past, present, and future uses; and points out risks and regulatory issues as Bitcoin interacts with the conventional financial system and the real economy.