ADA is a cryptocurrency coin that runs on Cardano Settlement Layer blockchain (CSL), the first and most secure blockchain based upon Proof of stake mechanism validating transactions. Their proof of stake mechanism is called Ouroboros by the Cardano team. Proof of stake is different from Proof of Work. Here, miners use energy-intensive computing power to mine each block. Proof of stake selects a random miner according to the stake's value. A slot leader is selected with a probability proportional the number of coins that this node has. This leader will then generate or mint a new block. ADA has an energy-efficient proof-of-stake transaction validation system, which is one of its advantages over Bitcoin, Ethereum, and similar cryptocurrencies. ADA can be used in a similar way to Ethereum thanks to a second layer Cardano Computational Layer, (CCL), which supports smart contracts and decentralized applications.
Input Output Hong Kong, a blockchain development company, created ADA. Charles Hoskinson, a co-founder of Etereum classic, Ethereum and Bitshares, led the project. Currently, the ADA team consists of three organizations i.e. Emurgo, IOHK and Cardano foundation.
Cardano's main use is for the transfer of value. Future applications on CCL layer will allow service providers like Uber and Upwork to easily and economically pay.