Cardano is a public blockchain platform that runs on proof of stake and uses a cryptocurrency called ADA to pay for transactions. It is a smart contract platform, which means developers can build decentralized applications and finance services on it, the same broad category as Ethereum. The network went live in 2017. Its token is named after Ada Lovelace, the nineteenth-century English mathematician often credited as the first computer programmer.
Cardano came out of a split inside the early Ethereum project. Charles Hoskinson, a co-founder of Ethereum, left in 2014, and with Jeremy Wood set out plans for Cardano in 2015. The two founded a company, IOHK, to build the technology. From the start the project took an academic approach: rather than a single founding white paper, Cardano is built from design principles and peer-reviewed research, and it has rolled out in deliberate, named phases over several years. That methodical style is the project's signature, and supporters and critics tend to argue over the same trait, whether the slow, research-first pace is a strength or a drag on shipping features.
The network secures itself with proof of stake through a protocol called Ouroboros. Instead of miners burning electricity to compete for blocks, as Bitcoin does, holders of ADA can stake their coins to help validate transactions and, in return, earn rewards. Staking can be done by delegating to a stake pool, so a holder does not need special hardware to take part. Proof of stake uses far less energy than proof of work, which is one of the points Cardano's backers make for it.
ADA is used to pay network fees, to stake for rewards, and to take part in governing the network's direction. People who want to hold it typically buy it on an exchange and keep it in a crypto wallet. As a smart contract platform, Cardano competes with a crowded field led by Ethereum and several faster, cheaper rivals, and its real-world usage is one of the open questions investors weigh against its research pedigree. The design delivers an energy-light network built on published academic work. Whether that careful approach wins the market it is competing in remains unsettled.