The Ethereum Name Service (ENS) is a look-up service that allows Ethereum users to find websites or send and receive funds via simple names instead of complicated sequences of letters and numbers. ENS features a registry smart contract that keeps track of all domain names, subdomains, owners, resolvers, and other information, as well as allowing the owner to update it. It works like the Domain Name System (DNS), but ENS is decentralized and more secure.
In cryptography, a salt is the additional random input that is added to password or passphrase to make the password hash unique. It prevents from the hashed output password to be cracked so easily by the hacker.