BitTorrent Sync (BTSync) is a file sharing system that relays on the BitTorrent protocol, and differs from other file sharing software in the connection type between devices. Instead of uploading the files to an online server, and then each device fetching them from the server itself, the file transfer is done directly from peer to peer, and therefore there is no limit on data storage and/or transfer speed.
BitTorrent Sync encrypts the traffic between devices with AES cypher and a 256-bit key created on the base of the secret — a random string (20 bytes or more) that is unique for every folder to be synchronized.
BitTorrent Sync uses a specific method for folder sharing, the 'secret': a random 21-byte key Base32-encoded.
When a device makes a folder and adds it to his BTSync client, a secret is generated. From now on, every device that wants to synchronize that folder, must know the secret key.
The synchronization has no speed or size limits, as long as both devices have enough disk space.
Once installed, enable the service:
# systemctl enable btsync
and initialize it, replacing 'user' by the desired username:
# systemctl start btsync@user
The Linux client of BTSync does not use a typical GUI; it sets up a WebUI server accessible in
localhost:8888, with the default login credentials as the user set in the service starting process, and the password
The web-server has the built-in configuration settings also available in other platforms.
For further configuration, the
~/.config/btsync/btsync.conf file contains advanced parameters; for example, the possibility to use a password other than the default one (recommended, of course).