Because the service uses P2P networking, it creates links to sync data between two machines rather than going through a cloud-based service first, such as Box or Dropbox. In fact, it works in pretty much the same way BitTorrent's other clients do. It uses peer discovery to find other computers set up for P2P connections. Then it links to existing hosts, trackers or Distributed Hash Table (DHT) networks to find its way to the target computer and authenticate to it.
Then it uses the same P2P protocols to check the status of files on each machine, break up into chunks any files that need to be exchanged, and encrypt them with 256-bit AES before hitting Send.
Like BitTorrent and other P2P software, Sync lets the user pick files or folders that should be available over the network. Sync also generates a 21-byte encryption key that the mobile device and home device use to authenticate to one another.
The service can also connect to any network-attached storage box running Linux on AMD, PowerPC, i386 or x86-based processors.
The BitTorrent blog announcing the release emphasized that the code is still in alpha and is likely to undergo a lot of fixes or changes before it even gets to the beta stage--it should be used only by those comfortable with products that could fail at any minute.
It lets users sync an unlimited number of files, sync files without any size limit, encrypt the data in transit using encryption keys controlled by the owner of the devices, and is flexible enough to act as a file-exchange system for co-workers as well as data-sync/backup for individuals. The software is the latest version of technology that has proven to be reliable and scalable in live deployments to non-technical users; the version that just entered alpha has already been tested by 20,000 users to sync more than 200 Tbytes of data, according to the developers.
The software is free, requires no additional services other than an IP connection and will run at the speed of any network available to the user.
While users may be pleased to have another file sync option, corporate storage, security and asset managers aren't going to be happy to see the new app. Aside from the security and content management difficulties that any file sync service presents, BitTorrent comes with its own baggage as a system for sharing content whose provenance and ownership may be unclear.
Using BitTorrent or other P2P apps isn't illegal, but traffic from them is suspect enough that many ISPs will throttle or block them on the assumption any significant P2P network traffic represents a copyright violation in progress.
Another issue for IT is that just because Sync bypasses a cloud provider's storage, there's a good chance Sync files will land on (and briefly be stored in) computers belonging to other people. Sync data uses the same peer-to-peer pass-along methods of other file-sharing clients, and its intermediaries are anonymous.
A good part of the design- and development work on P2P clients is specifically aimed at not making it easy for third parties to monitor who is connected to which machines and which files they're downloading. That may be an appealing feature to a user. To an IT department tasked with protecting valuable business content, it's yet another problem.