Siacoin (SC) is a utility token that powers the Sia Storage Platform, an open-source, decentralized cloud storage system. The Sia platform allows users to earn Siacoin by renting out spare hard drive capacity or store files using other people’s spare hard drive space paying them in Siacoin. The Sia blockchain is secured using a proof of work (PoW) consensus algorithm.

When a user uploads data to the Sia platform, it’s encrypted, divided into several smaller components, and stored on nodes all over the world. The only way to access the data is to decrypt it with the user’s private keys.

The Sia network utilizes storage smart contracts where both the “host” (storage provider) and “renter” (user uploading data) lock up some Siacoin in a smart contract escrow along with a transaction fee that the renter pays. After a specified time chosen by the renter, the system automatically checks to see if the data is still available from the host. If the host is offline or loses the encrypted data, they forfeit their staked Siacoins in the escrow account. If the host provides the encrypted data, their collateral is returned and they are paid via the smart contract.

The Sia platform also has a secondary, revenue-sharing token called SiaFunds (SF). This digital asset gives the holder a portion of the transaction fees each time a file is uploaded to the Sia network. The purpose of SiaFunds is to incentivize token holders to improve the storage platform by bringing on more users. With more people using the Sia network, SiaFund token holders receive more Siacoin.

There are only 10,000 SiaFunds and all have been pre-mined. At the time of this writing, Nebulous Inc., Siacoin’s parent company, owned over 8,000 SaiFunds and the remaining were sold in a crowdfund to help finance early development.

The idea for Siacoin was conceived in September 2013 by David Vorick and Luke Champine at HackMIT, a student-run hackathon held at the Massachusetts Institute of Technology. At that time, both Vorick and Champine were undergraduate computer science students at Rensselaer Polytechnic Institute in Troy, New York.

In May 2014, they cofounded the Boston-based company, Nebulous Inc., the core development team behind the Siacoin project. In that same month, Nebulous raised $240,000 from a SiaFund sale. In September 2014, it received a seed round of $750,000 from investors including Procyon Venture and angel investor, Xiaolai Li.

Less than one year, the first public beta of the Siacoin network was released in March 2015.

In July 2019, Nebulous closed a $3.5 million pre–Series A round led by Bain Capital Ventures, along with participants like Bessemer Venture Partners and Dragonfly Capital Partners.