BitTorrent released a beta version of a new Linux- and Android-ready peer-to-peer file sync package. BitTorrent Sync currently operates on Windows, Mac, and Linux PCs and laptops, Android smartphones and tablets, and an evolving list of Linux-based devices, including the Raspberry Pi and numerous NAS products, enabling on-the-go, secure uploads and sync from mobile to storage devices, as well as M2M/IoT scenarios.
Like the recent Plug Kickstarter project from Cloud Guys, BitTorrent Sync is touted as a DropBox alternative that avoids any potential privacy issues that might emerge with cloud storage. BitTorrent Sync is a different animal than the Plug, however. It’s a software-only product that draws on its flagship BitTorrent peer-to-peer (P2P) file sharing software to securely transmit and synchronize files.
BitTorrent Sync allows users to synchronize an unlimited number folders and files of any size across multiple devices, says the company. The software supports major desktop PC platforms, as well as Android (and soon iOS) devices and many embedded Linux devices. The latter include the Raspberry Pi and numerous network-attached storage (NAS) devices (see down below for a list).
As pointed out by Simon Sharwood in the Register, the support for mobile and NAS devices would enable Android smartphone or tablet users to transmit files to NAS devices where they can be accessible to other apps. Some NAS systems support mobile access to NAS contents, he notes, but few can update and sync NAS data as can BitTorrent Sync. This provides a capability that’s not currently available with Dropbox.
Like BitTorrent, BitTorrent Sync uses the P2P protocol to securely transfer files in pieces, with the algorithm optimized for maximum available bandwidth. Sync’d devices are connected via UDP, NAT traversal, and UPnP port mapping techniques.
BitTorrent Sync encrypts files using an AES cypher and a 256-bit key that operates using a “secret” — a random, 21-byte string that is unique for every folder. The Base32-encoded secrets are generated using “dev/random” on Linux or Mac platforms or Crypto API on Windows, says BitTorrent. An optional Base64-encoded “custom secret” function is said to add even more protection.
Free of intervention from third-party servers, BitTorrent Sync lets users “control and manage your secret keys so that all the files are stored only on your trusted devices,” says BitTorrent. Users can share temporary or permanent secrets, says the company.
A number of options are provided for discovering peers that share the same secret, including local peer discovery on a LAN, a peer exchange (PEX) between two users, a designated “known host,” and DHT (distributed hash table). Peer discovery is also said to be enabled via a BitTorrent tracker server. In “rare cases when peers can’t talk directly,” such as strong firewall intervention, BitTorrent will also supply an optional relay server, with communicates encrypted via AES.
Other features include one-way synchronization, file and folder exclusions lists, and versioning. The latter creates and stores all the old copies of edited files for 30 days in a hidden SyncArchive directory within the sync folder. Old versions of a file are marked by adding numbers to its name.
BitTorrent Sync Android app screenshots
(click images to enlarge)
BitTorrent Sync requires at least one of the following platforms:
- Android 2.2 and higher
- iOS 5.0 and higher (coming soon)
- Mac OS X Snow Leopard or later
- Windows XP SP3 (32-bit) or newer (32 and 64-bit)
- Linux with kernel 2.6.16 (glibc 2.4) or newer on ARM/PPC/i386/x86_64
The Linux support not only includes desktops, but embedded — mostly NAS — devices. The list, which is continuing to be updated, currently includes, but is not limited to:
- Synology Ds110j, Ds210j. DS211j, DS213+ (custom), DS211, DS411j, DS712+, DS713+, DS411 slim, DS-411+,DS411+II, DS412+
- QNAP TurboNAS TS-459 Pro II, TS410, TS-212, TS219, TS-110, TS412, TS-210
- Western Digital MyBook Live WDBACG0020HCH-00
- iOmega IX2-200
- ZyXel NSA310б NSA-221
- D-Link DNS-320
- Raspberry Pi
The BitTorrent Sync beta Android app in Google Play currently shows compatibility with our Google Nexus (10 and 7) and Samsung Galaxy devices (Note 10.1, Tab 7 plus, Galaxy S3), but does not appear to support our Google TV devices (Vizio Co-star and Logitech Revue) at this point.
The BitTorrent Sync beta software is available for free download at the BitTorrent Labs BitTorrent Sync product page. The BitTorrent Sync User Guide appears to be available for download from an Amazon S3 bucket, here (pdf file).