Abstract

This document provides a simple formal definition of Proof of Space (taken from the academic literature) and an informal definition of persistent and useful space (needed for Filecoin). It describes construction details and a security proof for the Stacked-DRGs proof of space (SDR), and goes into how SDR is used in Filecoin. In particular, it includes a description and analysis for Filecoin’s PoRep, WindowPoSt and WinningPoSt.