Syncthing replaces proprietary sync and cloud services with something open, trustworthy and decentralized. Your data is your data alone and you deserve to choose where it is stored, if it is shared with some third party and how it’s transmitted over the Internet.
Private. None of your data is ever stored anywhere else other than on your computers. There is no central server that might be compromised, legally or illegally.
Encrypted. All communication is secured using TLS. The encryption used includes perfect forward secrecy to prevent any eavesdropper from ever gaining access to your data.
Authenticated. Every node is identified by a strong cryptographic certificate. Only nodes you have explicitly allowed can connect to your cluster.
Once you get the idea of it, is very easy to use and set up. You can share folders of any sizes between multiple computers without the need of a 3rd party.