A cryptocurrency (or crypto currency) is a digital asset designed to work as a medium of exchange using cryptography to secure the transactions and to control the creation of additional units of the currency.

Cryptocurrencies are a subset of alternative currencies, or specifically of digital currencies.

The pound sterling (symbol: £; ISO code: GBP [Great Britain Pound]), commonly known as the pound, is the official currency of the United Kingdom, Jersey, Guernsey, the Isle of Man, South Georgia and the South Sandwich Islands, the British Antarctic Territory, and Tristan da Cunha.

It is subdivided into 100 pence (singular: penny, abbreviated: p).

A number of nations that do not use sterling also have currencies called the pound.

At various times, the pound sterling was commodity money or bank notes backed by silver or gold, but it is currently fiat money, backed only by the economy in the areas where it is accepted.

The pound sterling is the world's oldest currency still in use and which has been in continuous use since its inception.

Fiat money is a currency established as money by government regulation or law.

The term derives from the Latin ("let it become", "it will become") used in the sense of an order or decree.

It differs from commodity money and representative money.

Commodity money is created from a good, often a precious metal such as gold or silver, which has uses other than as a medium of exchange (such a good is called a commodity), while representative money simply represents a claim on such a good.

The United States dollar (sign: $; code: USD; also abbreviated US$ and referred to as the dollar, U.S. dollar, or American dollar) is the official currency of the United States and its insular territories per the United States Constitution.

It is divided into 100 smaller cent (¢) units.

The circulating paper money consists of Federal Reserve Notes that are denominated in United States dollars.

The euro (sign: €; code: EUR) is the official currency of the eurozone, which consists of 19 of the member states of the European Union: Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Portugal, Slovakia, Slovenia, and Spain.

The currency is also officially used by the institutions of the European Union and four other European countries, as well as unilaterally by two others, and is consequently used daily by some 337 million Europeans.

Outside of Europe, a number of overseas territories of EU members also use the euro as their currency.