Published on Feb 21, 2020
Sia is the first decentralized storage platform secured by blockchain technology. The Sia Storage Platform leverages underutilized hard drive capacity around the world to create a data storage marketplace that is more reliable and lower cost than traditional cloud storage providers.
Sia is an actively developed decentralized storage platform. Users all over the world contribute disk storage from their computers to form a decentralized network.
Anybody with siacoins can rent storage from hosts on Sia. This is accomplish via "smart" storage contracts stored on the Sia blockchain. The smart contract provides a payment to the host only after the host has kept the file for a given amount of time. If the host loses the file, the host does not get paid.
The distrubuted nature of the Sia network enables many optimizations in latency, throughput, reliability, and security. The decentralized nature of the Sia network enables anyone with storage to get paid, lowering the barrier to entry and reducing the overall price of cloud storage.
The Sia cryptocurrency is live! You can rent storage using siacoins and hosts providing storage to the network receive compensation in the form of siacoins. The storage platform itself is still in beta, and only uploads that are 500mb or less in size are supported by the wallet.
Sia encrypts and distributes your files across a decentralized network. You control your private encryption keys and you own your data. No outside company or third party can access or control your files, unlike traditional cloud storage providers.
On average, Sia's decentralized cloud storage costs 90% less than incumbent cloud storage providers. Storing 1TB of files on Sia costs about $2 per month, compared with $23 on Amazon S3.
Sia distributes and stores redundant file segments on nodes across the globe, eliminating any single point of failure and ensuring uptime that rivals traditional cloud storage providers
Sia’s software is completely open source, with contributions from leading software engineers and a thriving community of developers building innovative applications on the Sia API.
Using the Sia blockchain, Sia creates a decentralized storage marketplace in which hosts compete for your business, which leads to the lowest possible prices. Renters pay using Siacoin, which can also be mined and traded.
The Sia software divides files into 30 segments before uploading, each targeted for distribution to hosts across the world. This distribution assures that no one host represents a single point of failure and reinforces overall network uptime and redundancy.
File segments are created using a technology called Reed-Solomon erasure coding, commonly used in CDs and DVDs. Erasure coding allows Sia to divide files in a redundant manner, where any 10 of 30 segments can fully recover a user's files.
This means that if 20 out of 30 hosts go offline, a Sia user is still able to download her files.
Before leaving a renter's computer, each file segment is encrypted. This ensures that hosts only store encrypted segments of user data.
This differs from traditional cloud storage providers like Amazon, who do not encrypt user data by default. Sia is more secure than existing solutions because hosts only store encrypted file segments, rather than whole files.
Sia uses the Twofishalgorithm, an open source and secure encryption standard that was a finalist in the Advanced Encryption Standard (AES) contest.
Files Are Sent To Hosts Using Smart Contracts
Using the Sia blockchain, renters form file contracts with hosts. These contracts set pricing, uptime commitments, and other aspects of the relationship between the renters and the hosts.
File contracts are a type of smart contract. They allow us to create cryptographic service level agreements (SLAs) that are stored on the Sia blockchain.
Since file contracts are automatically enforced by the network, Sia has no need for intermediaries or trusted third parties.
Renters and Hosts Pay With Siacoin
Both renters and hosts use Siacoin, a unique cryptocurrency built on the Sia blockchain. Renters use Siacoin to buy storage capacity from hosts, while hosts deposit Siacoin into each file contract as collateral.
Micropayments flow between renters and hosts using a technology called payment channels, which is similar to Bitcoin's Lightning Network. Payments between renters and hosts occur off-chain, greatly increasing network efficiency and scalability.
Since hosts pay collateral into every storage contract, they have a strong disincentive to go offline.
