It’s funny. That was often said about general cloud computing when it became mainstream 10-15 years ago. Here’s how it works:
All over the world, there are zettabytes (billions of TB) of unused storage capacity. Rather than build massive, centralized data centers with proprietary equipment, Storj Labs acts as the Airbnb for disk drives. Storage node operators sign up to share their excess storage capacity and bandwidth with the network, committing to stay online at all times.
Then, when data is uploaded to the Storj network, it’s encrypted using AES 256-bit encryption (the same used by U.S. Military) and we use Reed Solomon erasure coding to build in redundancy so a file can easily be rebuilt from one-third of its pieces (any third). This makes it so that if any node goes offline, the network can easily rebuild the file from the other available pieces. The network is always constantly rebuilding missing pieces when nodes go offline.
All of these steps ensure data can be securely stored across nodes on the network in a way where it can never be lost.