SpaceMint (cryptocurrency)

SpaceMint, formerly known as Spacecoin (SPACE), is a cryptocurrency implementing a Proofs of Space protocol. Proof-of-space (PoSpace) protocols allow SPACE miners to be rewarded for dedicating disk space instead of dedicating computational power through proof-of-work protocols. Originally SpaceMint was called SpaceCoin, but the developers decided to change their projects name to SpaceMint due to name conflicts.

The proof-of-space (PoSpace) protocol implemented by SpaceMint disproportionately rewards small miners to incentivize miner participation and decentralization of the SpaceMint network. Across the SpaceMint network miners spend a fraction of a second per mined block, and use significantly less energy on ledger maintenance compared to proof-of-work networks used by other cryptocurrencies such as Bitcoin or Litecoin.

The PoSpace protocol requires more than two interactions compared to Proof-of-Work (PoW) consensuses mechanism, making the PoSpace consensus mechanism difficult to implement on the blockchain — this is known as the interactivity problem. The Interactivity problem is solved by SpaceMint creating a third interaction by using the Fiat-Shamir paradigm, which is a method of using a hash of a previous message to replace a public-coin challenge on the SpaceMint platform.