Sia is built in such a way that anyone is able to rent out extra space on their PC to the Sia decentralised network. It’s built around the use of Siacoin which is a special purpose currency for the Sia network that executes file storage smart contracts on the Sia blockchain. This means that the host has to keep the files for a previously specified time and in an previously specified space. After the end of the agreement, the payment will be released to the host in Siacoin. This is assured by the use of the smart contract. If the host loses the files then the smart contract is void and they won’t get paid. These smart contracts on the Sia blockchain ensure that both the user and the host will be satisfied. This is only possible with the use of the Siacoin cryptocurrency. Through the use of the blockchain and smart contracts, hosts get paid in Siacoin and ny user who wants to use Sia storage needs to pay Siacoins to a host.
One of the great advantages that the Sia platform offers is the incredibly low price of storing files. Sia currently offer a TB of cold storage for about $2 a month. In comparison to Amazon S3 (Simple Storage Service), which costs $23 a month, this is a saving of over 90%!
The first thing that happens is that the files that the users want to store are divided into 30 segments before being uploaded using the Sia software. Each segment is then distributed to a different host across the world. This assures that there isn’t a single point of failure which is generally present with centralised storage systems. Files segments are created using something called Reed-Soloman erasure coding that is commonly used in DVDs. This allows the files to be divided in a redundant manner and means that 20 of the 30 segments can be lost and the user is still able to recover their files.
Each file is then encrypted by the Twofish algorithm before it leaves the user’s computer to ensure that the hosts only handle encrypted data. As Sia is built on the blockchain it means that all user data is encrypted by default. In comparison to services like Amazon’s storage solution, Sia is theoretically much more secure as Amazon do not encrypt data by default.
These file contracts are paid for and secured using Siacoin. The users who want to store files can buy storage capacity from hosts using Siacoin. Hosts will have to deposit Siacoin into each file contract as collateral for the contract, this also provides a strong disincentive for host to go offline and lose the files. The payments between hosts and users all occur off-chain using something called a payment channel, that is said to be like the Bitcoin Lightning network. This means that the network can remain efficient and can theoretically scale much easier.
The renewal of these contracts can happen automatically and repayment for storage can be written into the initial contract. They typically last 90 days and if contracts are not renewed then Sia will return any unused coins to the user at the end of the contract period.
At the end of the contract the host must provide proof that they are storing the user’s data with something called storage proof. If this appears on the blockchain within a certain time then the host will be paid. Storage proofs are based on the technology of Merkle trees, the same technology used in Bitcoin. These make it possible to prove that data is part of a larger file whilst being very small in size themselves.
In 2014 the company was founded and the first round of funding was completed. In 2015 the company rolled out it the beta version of the Sia platform and in 2016 it was fully released. 2017 saw additional team members added and work continues on stabilising and improving the platform.
In 2018 they plan to have it completely production ready for cold storage and hope to see companies begin to use it. In 2019 they hope to start to reach similar speeds to Amazon S3 with an additional move towards warmer storage and introduce content distribution features. In 2020 they see themselves as a true competitor to Amazon S3 and expect companies to start to migrate to their platform.
David Vorick is the CEO and one of the co-founders of Sia. In addition to being the CEO, he is also one of the lead developers of Sia. He graduated from Rensselaer Polytechnic Institute with a BS in Computer Science.
Luke Champine is the other co-founder of Sia. Luke also studied at Rensselaer Polytechnic Institute with David but dropped out of college to work on Sia full time. He is Sia’s core developer with a passion for programming.
There is also direct competition from other crypto companies such as Storj and Maidsafe. In addition to this there are projects that aim to solve very similar problems. For example Oyster Pearl is looking to provide a decentralised cloud storage system whilst also offering a way for websites to monetise their content without the use of adverts.
Cons
A lot of the value of Siacoin and Sia will come from user adoption and currently this is looking quite promising. With the low prices that Sia is offering this is expected to continue.