1. Bitcoin (BTC): The first and most popular decentralized cryptocurrency.

Bitcoin is a decentralized digital currency, without a central bank or single administrator, that can be sent from user to user on the peer-to-peer bitcoin network without the need for intermediaries. It was invented in 2008 by an unknown person or group of people using the name Satoshi Nakamoto and was released as open-source software in 2009. Bitcoin transactions are verified by network nodes through cryptography and are recorded on a public distributed ledger called a blockchain. Bitcoin can be used as a medium of exchange for goods and services, as well as a speculative investment.cy.