Sia is a decentralized cloud storage platform similar in concept to Dropbox and other centralized storage provider where instead of renting storage space from a centralized entity, clients rent storage space from other peers. The only difference is Sia uses blockchain to facilitate transactions Nodes provide storage to clients using the Sia blockchain as contracts. Before storing the data, the data is encrypted into many pieces and uploaded to different hosts. Siacoin is created by David Vorick and Luke Champine of Nebulous Inc. As the traditional storage platforms are higher in cost, more expensive and data is not well protected. Siacoin promises to offer secured storage transactions with smart contracts which is more affordable and reliable. Moreover, it is completely open source which means many individuals have contributed to Siacoin’s software hence there will be an active community building innovative applications on top if the Sia API. In 2018, Siacoin aims to introduce file sharing and be the go-to cloud storage platform for companies. Their goal is divided into 3 time frames which are short-term, medium-term and long-term development. Short-term development focuses on file sharing between Sia users. This allows Sia users to share files in the platform without having to take it off the cloud while increasing network utilization. Medium-term development’s goal is to enhance partnerships. This means reaching out to large companies like Netflix and Dropbox to hopefully be able to be their storage and distribution framework. Lastly, long-term development aims to expand its horizon to share files with non-Sia users and support mobile wallets.
The Cosmos network consists of many independent, parallel blockchains, called zones, each powered by classical Byzantine fault-tolerant (BFT) consensus protocols like Tendermint (already used by platforms like ErisDB). Some zones act as hubs with respect to other zones, allowing many zones to interoperate through a shared hub. The architecture is a more general application of the Bitcoin sidechains concept, using classic BFT and Proof-of-Stake algorithms, instead of Proof-of-Work.Cosmos can interoperate with multiple other applications and cryptocurrencies, something other blockchains can’t do well. By creating a new zone, you can plug any blockchain system into the Cosmos hub and pass tokens back and forth between those zones, without the need for an intermediary. While the Cosmos Hub is a multi-asset distributed ledger, there is a special native token called the atom. Atoms have three use cases: as a spam-prevention mechanism, as staking tokens, and as a voting mechanism in governance. As a spam prevention mechanism, Atoms are used to pay fees. The fee may be proportional to the amount of computation required by the transaction, similar to Ethereum’s concept of “gas”. Fee distribution is done in-protocol and a protocol specification is described here. As staking tokens, Atoms can be “bonded” in order to earn block rewards. The economic security of the Cosmos Hub is a function of the amount of Atoms staked. The more Atoms that are collateralized, the more “skin” there is at stake and the higher the cost of attacking the network. Thus, the more Atoms there are bonded, the greater the economic security of the network. Atom holders may govern the Cosmos Hub by voting on proposals with their staked Atoms.