The cryptocurrency that uses proof of space and time is Chia.
Chia Network was founded in 2017 by Bram Cohen, the creator of BitTorrent, and designed its blockchain around Proof of Space and Time. Instead of relying primarily on computational work like Bitcoin’s proof-of-work system, Chia participants allocate storage capacity to create cryptographic plot files and demonstrate that the space remains committed over time.
Chia calls participants farmers rather than miners. Farmers keep plots on storage devices and submit proofs when challenges arrive, while a time component supplied by specialized network services helps establish the passage of time between blocks. Chia’s native currency is called Chia, with the ticker XCH.
Chia is sometimes confused with Filecoin, Storj, or Siacoin because all involve storage-related ideas. Chia’s plots generally do not store useful user files; they support consensus. Proof of capacity and proof of space are related concepts, but Chia specifically combines space with time in its consensus design.