How safe is my media in SiaStream?

Your media is uncomparably safe when it's in SiaStream. The Sia network, where SiaStream stores your data, has been operating since 2015, hundreds of terabytes are currently being stored on it, and thousands of terabytes have been stored over the years.

Sia is decentralized, which has a bunch of inherent benefits. While we develop the software, we're not in charge of the network. No one is - it's all handled by smart contracts and the blockchain, and Sia is completely open source so you can make sure we're staying honest.

When we think of the safety of your data, a few things come to mind.

  • Privacy. You should be the only person who can see your files.
  • Security. You shouldn't ever lose your data or be denied access to it.


Peer to peer data storage sounds weird. Your files are being stored all over the world on other people's hard drives. It's an obvious thing to be concerned about, and we're happy that so many users care about this question.

Here's the short answer: Your data is never viewable by anyone but you.

But that's easy for us to say.

Split it

When you upload your media to SiaStream, every single file gets divided into 30 segments before uploading, each targeted for distribution to hosts across the world.

File segments are created using Reed-Solomon erasure coding, commonly used in CDs and DVDs.

Encrypt it

Each file segment is encrypted before being sent out.

Sia uses the Threefish algorithm, an open source, secure, high-performance encryption standard.

Because your files are split and encrypted, no host ever stores a complete piece of your data. And they can't even see the piece that they've got.


The technical side

Like we mentioned earlier, Sia divides each files into 30 segments before uploading, and puts those pieces all over the world. This distribution assures that no one host represents a single point of failure and reinforces overall network uptime and redundancy.

The Reed-Solomon 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 their files. And when hosts go offline, Sia automatically starts to re-duplicate them again. It would take a simultaneous global event to knock out enough hosts to damage the integrity of your files.

And because Sia is decentralized, no one person, company, or government can deny you access. It's global and governed by no one.

The economic side

Just as important as how it keeps your data secure, is why. The Sia network keeps your data safe because data hosts are financially incentivized to provide enterprise level service. Individual hosts who store your data:

  • must keep uptime greater than 95%
  • have a period where they must prove your data has been stored

...That 95% number doesn't sound enterprise level. And it wouldn't be, if you only had the one host. But you have 30, and only need 10 of them to be online at any time to retrieve your data. On top of that, if your number of hosts drops, Sia automatically repairs your files by finding new hosts. In practice, Sia has an effective uptime of well over 99%.

And contracts are front-loaded, meaning hosts have already deposited some money that they want to make sure they get back. This is how hosts are held to their word - they're able to be automatically financially penalized, and must agree to these terms to earn their revenue.

How did we do?

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