Bittorrent Sync: Security Is Our Highest Priority

http://forum.bittorrent.com/topic/32592-bittorrent-sync-security-is-our-highest-priority/

by mseri • 12 years ago

80 40 12 years ago

forum.bittorrent.com

RRRA• 12 years ago

Still closed source...

jrochkind1• 12 years ago

it is a 160 bit number, which means that it is cryptographically impossible to guess the hash of a specific folder.

Perhaps they know what they're talking about and are just trying to simplify for a non-technical audience... but that kind of language does not inspire confidence from a technical audience.

tptacek• 12 years ago

... because...

SCHiM• 12 years ago

Because saying it like sounds like they are merely using buzzords instead of clearly stating why their system is secure. To me it seemed that the intended result for the user was to think:

"super cryptographically secure 160bit secret folders!"

While they should have gone for:

Our algorithm to hash folders produces hashes 160bits long. Which means that 2^160 -1 different folders can be securely hashed!

Of course they diden't say what they meant with 'secure' either. Will two folders that are both very big, and only differ with 1 bit produce the same hash yes or no? Is it possible to reverse this hash easily? Can it be brute forced? That kind of stuff...

Having said that, it does appear that this post was aimed at non-technical users. So perhaps it's not a bad way to rebut the claims about leaky security.

daeken• 12 years ago

I think the use of "cryptographically" there is a bit silly, but otherwise they're spot on. You could have a billion computers, each trying a billion unique guesses per second, for a billion years, and you would've only guessed 0.000000000002158% of the possible values.

160 bits is a lot of bits.

pbsd• 12 years ago

Well, it would depend on the entropy of the folder. Maybe we know the general structure of the folder, except some crucial short piece of information. Otherwise, everyone would also be fine using SHA-1 to store passwords.

N.B: I don't know anything about the protocol, or whether the above applies. But appealing to the strength of a hash function only makes sense for hard-to-guess hashing material, which is not always the case.

e12e• 12 years ago

Right. But as I read it, the 160bit hash is over the content, in order to find peers with the same content. So if I wonder who's got a certain leaked document, or a certain media file, the hash can be used to xheck for that? Could be enoygh to get a warrant, for example? If I know a certain document, say payslip.pdf and guess it is in a folder named payslips - maybe I could guess the other values and verify my guess with the hash (yeah, probably not a very interesting example ...)

eps2• 12 years ago

While it's a pure implementation issue, it's odd that they haven't at all addressed app's crashing through packet fuzzing, because that's an excellent zero-day candidate.

ef4• 12 years ago

I'll believe you when you open source it.

I've been using syncthing and it's pretty great.

toggle• 12 years ago

BitTorrent Sync remains the most secure and private way to to move data between two or more devices.

That very first sentence will always be false as long as it isn't open source. (Even the protocol isn't publicly documented, last I checked.) I'm not an open-source purist, but the way they always promote as being the most secure, private option out there while completely ignoring that fact is frustrating.

I haven't tried using it, but Pulse[0] appears to be an open source replacement for BitTorrent Sync. I figure it's relevant to this thread.

[0] https://ind.ie/pulse/

EDIT: ef4 mentioned Syncthing in his comment. Pulse was forked from Syncthing. I think they're still compatible with each other at the moment. Nice explanation at https://discourse.syncthing.net/t/syncthing-is-still-syncthi....

trickz2• 12 years ago

How would open sourcing it make it more secure? I mean, I understand that doing so would let you look at the code, and maybe even have others find and plug security holes, but your statement seems to imply that closed source is less secure by default, unless I'm missing something.

mkonecny• 12 years ago

Doesn't necessarily make it more secure, but will increase the confidence that it is the most secure through peer review. Any company will say their products are secure/the best etc. - proof is what makes those claims legit.

5293qhofeo• 12 years ago

Security is a poor word, but if we define it as quality (reliability, fitness for a stated purpose, logical consistency, etc), then access to source code allows peer and public review. IMHO, free software is just the scientific method (loosely) applied to programming (with a moral context). Test-driven development is an attempt to tighten up the hypothesis-implementation-analysis loop.

jaseemabid• 12 years ago

The last time I installed bittorrent on my mac, it came with a chrome extension malware. I used to really love BTSync, but now I'm certainly going to ditch it.

For once again proving the point that unless its free software, its not worth it.

Bittorrent Sync: Security Is Our Highest Priority

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