sia is a Decentralised cloud storage platform that operates on a blockchain. It was introduced on November 29, 2014. Its primary function is to create storage contracts between peers in its network. Distinct from centralised cloud storage, Sia enables peers to rent storage from each other with contracts that are stored on the Sia blockchain. Sia uses a cryptocurrency called Siacoin (SC) to enable transactions within its network. The platform ensures providers prove continued data storage to their clients and compensates them for this service using Siacoin. While it initially operates as an altcoin, Sia plans to incorporate a two-way peg to Bitcoin, making it a sidechain that can leverage Bitcoin's security and capital while preserving its unique characteristics for Decentralised storage.