What is Proof of Spacetime (PoSpacetime)?

Proof of Spacetime (PoSpacetime) is a consensus mechanism utilized by the Filecoin network. It allows the blockchain to prove its capacity, and in doing so, it can cryptographically verify that the entire file is being stored in an unaltered fashion for an agreed-upon time frame. Proof of Spacetime is made up of two distinct subsets: 1.) Window Proof of Spacetime (WindowPoSpacetime) and 2.) Winning Proof of Spacetime (WinningPoSpacetime).