sia_nemo

Don't trust us, trust the code! Sia is 100% open source.

In a way, this is better than trusting a company like Google or Microsoft with your data. They are storing all of your personal information unencrypted, and they're a single point of failure. If Google decides that you violated their terms of service (which has happened to many innocent people in the past), they can lock you out of your account with no warning. That sort of scenario can never happen on Sia.

Sia: Weeb tested, NEET approved.

You make an interesting point. The primary innovation of Sia is to remove trust from the equation, and that comes with some tradeoffs. When you are storing your data across dozens of untrusted nodes, you have to handle the redundancy yourself. However, there is nothing stopping you from uploading to a single host if you trust them 100% to maintain the durability of your data. But there are also tradeoffs to that approach; specifically, if your data only resides in one datacenter, you can't download it in parallel, and the latency is a function of your distance from that one datacenter. Splitting the data across multiple hosts allows for parallel uploads and downloads and evens out latency numbers, much like a CDN.

One of the things we value about Sia is that it makes pricing very transparent. You pay for exactly what you use, including both storage costs and bandwidth costs. There are no pricing tiers, and you are never "locked-in" to using a particular host. Our vision is a competitive marketplace for storage, where hosts compete purely on what matters: availability, latency, bandwidth, price.

Nope, that isn't the secret :)

A price reward is an interesting idea. Currently we rely on the local host database to weight hosts according to various factors. For example, a host with 90% uptime should be weighted much higher than a host with 70% uptime. Higher weight == higher probability that the renter will form a contract with that host. So there is already a soft guarantee that higher uptime results in more profits. And of course, more uptime means the host is more likely to be online when an upload/download is requested; otherwise they miss out on that revenue.

The coins are held in an escrow of sorts, enabled by the smart contract.

Blockchains use consensus algorithms to decide who is allowed to spend what. The most common example is that only the owner of a private key is allowed to spend some volume of coins. For Sia, we added new consensus rules that govern how funds in a smart contract may be spent. Once the contract is created, the funds are "tied up" for the duration of the contract; neither renter nor host has the ability to spend them. During the contract, they can move these allocated funds back and forth (for example, to pay for some storage). When the contract ends, every Sia node checks whether the terms of the contract were fulfilled, and uses that to decide who to release the funds to. If the contract was successful, the funds go to the host; otherwise they are returned to the renter. This is also known as a payment channel.

As for your related question: currently, hosts are only required to prove that they still have the uploaded data at the time the contract concludes. Proof of capacity is a tricky thing. We did some exploratory work on it a while ago, but judged that it wasn't mature enough to add to Sia. Fortunately, it shouldn't be difficult to add later if the research coalesces a bit.