BitTorrent announced on Wednesday that BitTorrent Sync has moved into beta. It's essentially a P2P client for your local network, allowing users to sync files between connected devices for sharing and backup purposes. Folders that sync are connected by a common "secret", or rather a private key, that is unique for every sync folder.
To sync a specific folder to other devices, the user first clicks "Generate" to create a new secret. This secret must be then entered on all the devices the user wants to sync. If a BitTorrent Sync user is joining an already established sync network, they must enter an existing secret that someone has shared. Users can also choose to generate a read-only secret for synchronizing information from one device only, and a one-time key that can be used only once and expires after 24 hours.
"You can use it for remote backup," the company said on Wednesday. "Or, you can use it to transfer large folders of personal media between users and machines; editors and collaborators. It’s simple. It’s free. It’s the awesome power of P2P, applied to file-syncing."
Now that BitTorrent Sync is in beta, the team has introduced two new features: mobile apps and an archive capability for retrieving previous versions of synced files. For starters, BitTorrent is only offering an Android app during the beta's launch (iOS is expected to follow soon), allowing users to sync folders with computers, send files to other mobile devices with BitTorrent Sync installed, or back up pictures and videos.
Setup is easy. After installing the app, users must select or create a destination folder on their Android device to sync – one on a mounted secondary SD card would be ideal. After that, the user must generate a QR code on the folder to be synced on the PC. This code is scanned by the BitTorrent Sync Android app, thus connecting the two devices. Throw an MP3 album into the folder on the PC, and it's automatically uploaded to the Android device's SD card. To sync files outside the local wireless network, users must turn on "Use Cellular Data" in the Settings menu to enable file syncing on a 3G or 4G connection.
As for SyncArchive, it's a feature that's been in high demand ever since the alpha launched in April. The team describes it as a basic versioning capability, and will include a folder where users can see all previous versions of their files. It's unobtrusive and searchable, the team said, and will evolve over time.
"BitTorrent Sync was designed to solve for what we see as real, fundamental challenges to data synchronization: limitations on speed, size, and space; limitations on file security and dependency on cloud infrastructure," the team said. "Because BitTorrent Sync is based on the principles of the BitTorrent protocol, you can sync as many big files as you want. Transfers are encrypted, and information isn’t stored on any server, or in the cloud. Your content belongs to you, and stays on devices of your choice. That’s the way syncing should work."
For now, BitTorrent Sync works on Mac OS X Snow Leopard or later, Windows XP SP3 (32-bit) or newer (32 and 64-bit) and Linux with kernel 2.6.16 (glibc 2.4) or newer on ARM/PPC/i386/x86_64. The client can also be installed on NAS devices running on Linux with ARM, PowerPC, i386 and x86_64 architecture.
The team said that users can sync unlimited files of any size between their own devices, or share a folder with friends or family. That suggests the 21-byte keys can be given to anyone outside the local network, and is a stronger, more secure method than using the typical login/password combination. This key is Base32-encoded in order to be readable by humans, the team said.
"There are rare cases when peers can’t talk directly. This usually happens when devices are in an office behind strong firewalls," the team said. "In such a case BitTorrent provides a relay server to route traffic between peers. All traffic is AES encrypted with your secret, so there is no chance for us to see any of your data. You can opt out of this, but it could result in peers not being able to network with each other."
We contacted the BitTorrent Sync team to verify that folders can be shared with other computers outside the home network – obviously it's possible with an Android smartphone. For instance, could someone create a folder, throw in a plethora of family pictures, generate a key, and sync that folder to family members (mom) in another state?
"That very scenario you describe is exactly the inspiration behind Sync," a BitTorrent rep said in an email. "The engineer wanted to share photos with his family and friends. And yes, as long your mom has Sync loaded up she will automatically get anything you put into a shared folder once she has the key."
Will this solution open the door to a next-generation of illegal file sharing? According to an FAQ on how BitTorrent Sync works, files can be viewed and received only by the people with whom the user shares their private secret (key). That means it's possible to set up a shared folder full of illegal content, and provide a read-only key on a forum for users to sync.
"If you are concerned about security, BitTorrent Sync provides opportunity to regularly generate new Secrets for a folder, or replace an existing secret with your own Base64 string more than 40 characters long. The new folder Secret should be re-entered on all the devices in sync," the FAQ reads.
In a separate email, BitTorrent had this to say about online privacy. "With all of the NSA and PRISM developments of late, consumers are more keenly aware of online privacy and digital security issues," the company stated. "As BitTorrent Sync doesn’t rely on servers, your data is never exposed to prying eyes. No servers also means Sync does not contribute to the environmental and energy concerns that have surfaced with the cloud."
"Likewise, Sync is built in such a way that the product will never shut down," the company added. "The software will be as usable (and free) in the future as it is today. The user is always in control of their own data."
Since April 2013, more than 8 petabytes of data has been synced between BitTorrent Sync Alpha users. To put that into context, the Internet Archive, one of the World Wide Web’s largest repositories of media, houses 10 petabytes of data. BitTorrent Sync is already a huge success, and it's about to get even bigger now that the service has kicked into beta.