Bitcoin was published in 2009, which makes it the first and most important cryptocurrency. It was invented by "Satoshi Nakamoto", whose real identity is unknown. Bitcoin consists of a monetary unit and a payment system. The digital currency (BTC) is created and managed in a global, decentralised computer network using a special software solution. The global system is like a decentralised database in which all transactions are logged in the form of a blockchain. Bitcoin attracted worldwide attention in 2017 as it increased in value.

Ether (ETH) is the internal payment system for processing transactions for the global platform Ethereum. The Ethereum platform is used for Distributed Apps and allows the creation, execution, and management of smart contracts.

Litecoin (LTC) is a global and decentralised payment network similar to the Bitcoin network. The essential differences between Litecoin and Bitcoin are in the technology. Key aspects are the transaction speed, the maximum offering of the coins concerned and the algorithm used.

Ripple (XRP) is an open-source protocol based on a public database. The Ripple network supports all standard currencies. XRP appeared in 2012 and, unlike Bitcoin, is not based on the blockchain and the coin cannot be mined.