Cardano is a decentralised public BLOCKCHAIN and cryptocurrency project under development and is open source.
From its website: Cardano is a decentralised public blockchain and cryptocurrency project and is fully open source. Cardano is developing a smart contract platform which seeks to deliver more advanced features than any protocol previously developed. It is the first blockchain platform to evolve out of a scientific philosophy and a research-first driven approach. The development team consists of a large global collective of expert engineers and researchers.
How Does Cardano Work?
What is Cardano ADA? Programmer explains.