Cardano, founded in September 2017 by Ethereum co-founder Charles Hoskinson, is an open-source, decentralized blockchain network and smart contract platform. Ada (ADA) is its native cryptocurrency.
Cardano is described as a third-generation blockchain, with Bitcoin and Ethereum being examples of first- and second-generation networks, respectively. The team behind the project comprises leading scientists and engineers from three independent blockchain companies, and the project's development is extensively reviewed.
Cardano's current proof-of-stake consensus algorithm is called Ouroboros Genesis, which is in its third iteration. This protocol is less energy-intensive than Bitcoin's proof-of-work and can process more data per second than Ethereum.
Rather than relying on expensive mining hardware, Cardano's stakers hold ADA and stake it via a Cardano full node. The protocol elects a group of staking nodes at random to become "slot leaders" for periods of about five days, called "epochs."
Each epoch is subdivided into slots and assigned a slot leader. Only slot leaders can add blocks of transactions to the chain and must do so during their assigned slots. A slot leader receives newly minted ADA only if their block is valid. By allowing multiple epochs to run in parallel, Cardano transactions and computations remain cheap and fast, irrespective of network demand.
Moreover, the Cardano blockchain features a multi-layered design. The layer on which ADA transacts is called the Cardano Settlement Layer. A second layer, the Cardano Computation Layer, allows the deployment of smart contract-based decentralized applications. Unlike Ethereum and other smart contract networks, ADA transactions are not competing with DApp computations for block space.