Silk Road forums
Discussion => Security => Topic started by: vlad1m1r on April 13, 2012, 09:14 pm
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A really excellent article from Bruce Schneier's security blog:
April 13, 2012
Disguising Tor Traffic as Skype Video Calls
One of the problems with Tor traffic is that it can de detected and blocked. Here's SkypeMorph, a clever system that disguises Tor traffic as Skype video traffic.
To prevent the Tor traffic from being recognized by anyone analyzing the network flow, SkypeMorph uses what's known as traffic shaping to convert Tor packets into User Datagram Protocol packets, as used by Skype. The traffic shaping also mimics the sizes and timings of packets produced by normal Skype video conversations. As a result, outsiders observing the traffic between the end user and the bridge see data that looks identical to a Skype video conversation.
The SkypeMorph developers chose Skype because the software is widely used throughout the world, making it hard for governments to block it without arousing widespread criticism. The developers picked the VoIP client's video functions because its flow of packets more closely resembles Tor traffic. Voice communications, by contrast, show long pauses in transmissions, as one party speaks and the other listens.
See more here (http://www.schneier.com/blog/archives/2012/04/disguising_tor.html)
So now there's finally a way to have Plausible deniability for Tor... except in all those oppressive regimes where Skype is banned too!
V.
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This is really cool but I can't see where it's undergone extensive review. So I would continue to use the Tor Project's protocol obfuscator which is being actively maintained and took no small amount of effort to review and push out.
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This is really cool but I can't see where it's undergone extensive review. So I would continue to use the Tor Project's protocol obfuscator which is being actively maintained and took no small amount of effort to review and push out.
Thanks for the post QTC. I've just had a peek at ObfuscaTOR and it seems that this is a way of disguising the identity of Tor Bridges. Forgive my ignorance but surely it would still be possible to detect someone was using a Torified connection if they did this? It just wouldn't be possible to block them from accessing Tor bridges?
V.
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It's obfsproxy, not obfuscator.
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This is really cool but I can't see where it's undergone extensive review.
It hasn't. Think of it as a prototype that still needs testing and debugging and long term maintenance.
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Indeed, in the past many of us considered Skype a security risk due to its behavior and protocol construction. There were also suspicions that, after eBay acquisition, that it was operated by the NSA. How ironic that they would proxy an anonymity system through a privacy-defeating, possibly government run product.
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Indeed, in the past many of us considered Skype a security risk due to its behavior and protocol construction. There were also suspicions that, after eBay acquisition, that it was operated by the NSA. How ironic that they would proxy an anonymity system through a privacy-defeating, possibly government run product.
Skype Technologies unwillingness to share their source code was a little suspicious. In the past it's been fairly trivial for Police to intercept Skype calls - the German Police had publicly admitted as much.
I have posted about secure VOIP in another thread - my personal favourite is using the app Jitsi which supports ZRTP encrypted calls.
V.