BitTorrent has opened the Alpha testing program for its new BitTorrent Sync tool to all.

Announced last January but only available to a select few, BitTorrent Sync looks a bit like the numerous DropBox-without-the-cloud-in-the-middle contenders inasmuch as it lets you set up a source of data, then involve trusted third parties whose machines will sync with the source. The tool is offered for Windows, MacOS and Linux, the latter in a form that can be installed on computers or “... on Network Attached Storages (NAS) running on Linux with ARM, PowerPC, i386 and x86_64 architecture.” Plenty of commercial NAS devices meet those requirements and this forums thread reports on several that seem to have successfully put the software to work.

BitTorrent says the technology involved is “very similar to the powerful protocol used by applications like µTorrent and BitTorrent.”

Data “is transferred in pieces from each of the syncing devices, and BitTorrent Sync chooses the optimal algorithm to make sure you have a maximum download and upload speed during the process.”

All traffic exchanged among peers is encrypted “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.” It's also possible to create one-time secrets to enable a single file transfer, with such passkeys expiring after 24 hours.

The UI of BitTorrent's new Sync tool

BitTorrent is a powerful file distribution technology with many legitimate uses and users, but is tainted by its widespread use for sharing copyrighted material and unofficial association with notorious sites like The Pirate Bay.

This new Sync application may not remove that taint, as it also offers a peer exchange that means “When two peers are connected, they exchange information about other peers they know.” It's not hard to imagine large networks of peers emerging as the tool spreads. Other features also suggest it will be possible to establish large networks of peers, with BitTorrent Sync capable of using trackers “to facilitate peer discovery.”

NAS vendors, however, may welcome the new software, as many have in the past incuded BitTorrent clients in their products. Bittorrent Sync is free for now and there's no indication of whether or not it will eventually come at a cost. Even if it does, NAS syncing between NAS boxen and other computers is clearly a useful function that manufacturers may be willing to shell out for in order to improve their boxes' cloud cred.

Even if that doesn't happen, the thread we've linked to above reports Raspberry Pi users have made the new software work under Raspbian, which makes the tiny computer an even more tempting home-brew storage manager. ®