Chia is a cryptocurrency described by its creator Bram Cohen, as green money for a digital world.
First things first though, who is Bram Cohen? Bram in case you do not already know revolutionized file transfers through peer-to-peer by inventing torrents! His newest creation comes in the form of a cryptocurrency that tries to solve the huge amounts of electrical energy required for cryptos that use proof-of-work to secure their transactions (like Bitcoin) and instead uses proof-of-space.
This process will use hard disk space instead as the transaction confirmation mechanism and as Cohen mentioned everyone seems to have excess storage on their desktops or laptops or even mobile devices. He also claimed that Chia’s network will be even safer when it comes to defending itself from attacks as you the cost would be even higher than trying to mount an attack against the Bitcoin network.
However to prevent the possibility of re-mining from a genesis attack (creating essentially a new blockchain with the purpose to switch with the original) an additional measure is introduced with a proof-of-time mechanism. It is still possible for years of work to be rewritten for a potential attack to happen but it will definitely be very time-consuming and costly to do so. Chia does not yet have a release date, as the programmed launch for end of 2018 was delayed.