A bitcoin address is a string of characters that represents a wallet that can send and receive cryptocurrency. It is akin to a real-life address, email or website. Every address is unique and denotes the location of a wallet on the blockchain.

Air gap

An isolated computer or network which has no network interfaces connected to other networks, with a physical (or conceptual) air gap (not connected to the Internet).


Airdrop (or crypto airdrop) is when a blockchain project distributes free tokens or coins to the crypto community. To be a recipient of a crypto airdrop often the only requirement is that you have coins from the relevant blockchain stored in your wallet. Examples of this format of airdrops are Byteball, Stellar lumens and OmiseGo.


In mathematics and computer science, an algorithm is a finite sequence of well-defined, computer-implementable instructions, typically to solve a class of problems or to perform a computation. Algorithms are always unambiguous and are used as specifications for performing calculations, data processing, automated reasoning, and other tasks.


Altcoins are cryptocurrencies other than Bitcoin. The majority of altcoins are forks of Bitcoin with small uninteresting changes. This page categorises different ways altcoins have modified Bitcoin. Many people prefer the term "shitcoin" to clearly distinguish all these altcoins from Bitcoin. This term has even been used in US Congress in 2019.

Application Programming Interface (API)

An application programming interface (API) is a computing interface that defines interactions between multiple software applications or mixed hardware-software intermediaries. It defines the kinds of calls or requests that can be made, how to make them, the data formats that should be used, the conventions to follow, etc. It can also provide extension mechanisms so that users can extend existing functionality in various ways and to varying degrees. An API can be entirely custom, specific to a component, or designed based on an industry-standard to ensure interoperability.

Application Specific Integrated Circuit (ASIC)

An application-specific integrated circuit (abbreviated as ASIC) is an integrated circuit (IC) customized for a particular use, rather than intended for general-purpose use. In Bitcoin mining hardware, ASICs were the next step of development after CPUs, GPUs and FPGAs. Capable of easily outperforming the aforementioned platforms for Bitcoin mining in both speed and efficiency, all Bitcoin mining hardware that is practical in use will make use of one or more Bitcoin (SHA256d) ASICs. Note that Bitcoin ASIC chips generally can only be used for Bitcoin mining. While there are rare exceptions - for example chips that mine both Bitcoin and scrypt - this is often because the chip package effectively has two ASICs: one for Bitcoin and one for scrypt. The ASIC chip of choice determines, in large part, the cost and efficiency of a given miner, as ASIC development and manufacture are very expensive processes, and the ASIC chips themselves are often the components that require the most power on a Bitcoin miner. While there are many Bitcoin mining hardware manufacturers, some of these should be seen as systems integrators - using the ASIC chips manufactured by other parties, and combining them with other electronic components on a board to form the Bitcoin mining hardware.


In economics and finance, arbitrage is the practice of taking advantage of a price difference between two or more markets: striking a combination of matching deals that capitalize upon the imbalance, the profit being the difference between the market prices at which the unit is traded. When used by academics, an arbitrage is a transaction that involves no negative cash flow at any probabilistic or temporal state and a positive cash flow in at least one state; in simple terms, it is the possibility of a risk-free profit after transaction costs. For example, an arbitrage opportunity is present when there is the possibility to instantaneously buy something for a low price and sell it for a higher price.

ASIC Miner

An ASIC Bitcoin miner is designed exclusively for the purpose of mining bitcoin. Though significantly more expensive to purchase, they are far more powerful (higher hash rate) and electricity-efficient than CPUs and GPUs (graphics cards) – used for mining in the early days of bitcoin – and even FPGAs (field programmable gate arrays), which were, in 2011, the most efficient option. According to Mike Murray, creator of The Geek Pub, a $2500 ASIC miner is as powerful as 400 GPUs, or 12,000 CPUs, which would cost $18 million. For reference, as of February 2018, the Bitmain Antminer S9 possessed the highest available hashrate at ~14 TH/s, with an efficiency of ~0.1 Joule per GH/s, and cost $3200 on Amazon, not including the power supply. ASIC for bitcoin mining hardware Mining is now so competitive, and the difficulty rate so high, that attempting to do so without an ASIC is unprofitable. Because ASIC mining hardware is so expensive, ASIC for bitcoin mining is done by companies in thermally-regulated data-centers with access to low-cost electricity. Many of these companies lease part of their mining power as a service.

Atomic Swap

Atomic swaps are a mechanism where one cryptocurrency can be exchanged directly for another cryptocurrency, without the need for a trusted third party such as an exchange.