7 ms·

Given the extent of the five eyes (NSA,GCHQ,DSD, etc) taping of major fiber lines, Tor is almost certainly useless against the NSA even without backdoors. The N

Given the extent of the five eyes (NSA,GCHQ,DSD, etc) taping of major fiber lines, Tor is almost certainly useless against the NSA even without backdoors. The NSA doesn't need to resort to expensive key cracking operations to break either the anonymity or confidentiality of Tor. They just have to be able to see entry and exit node traffic. From the original paper by the Tor developers: "A global passive adversary is the most commonly assumed threat when analyzing theoretical anonymity designs. But like all practical low-latency systems, Tor does not protect against such a strong adversary." --- Tor: The Second-Generation Onion Router http://www.dtic.mil/dtic/tr/fulltext/u2/a465464.pdf http://www.dtic.mil/dtic/tr/fulltext/u2/a465464.pdf

aegiso 13y ago
So I'm totally making stuff up here, and my interest in crypto has a hackish rather than academic flavor, but... Couldn't we design a system that doesn't fall in this scenario, by using a constant-rate packet-blasting network that emits "background radiation" even if nothing is happening, and then filters out the good stuff via chaffing/winnowing [1]? This would clog the tubes like a torrent and run you a similar tab, but wouldn't it be 100% anonymous even in the face of such an adversary, while still being low-latency? [1] http://en.wikipedia.org/wiki/Chaffing_and_winnowing http://en.wikipedia.org/wiki/Chaffing_and_winnowing
- sillysaurus2 13y ago
  Yes, but Tor is already very slow, and it has a lot of resources behind it already. It would take a substantial amount of money to bootstrap your network. It'd be a worthy 1-10MM investment --- assuming you don't want any ROI on it.
- simcop2387 13y ago
  Freenet actually does this, though they aren't just sending random chaff, they'll actually use it to duplicate the data. It makes this particular attack impossible, but freenet has it's own potential issues. If you control all of someone's inputs and outputs you can still determine when they are using the system.
- Shish2k 13y ago
  I'm working on something along those lines at the moment - constant rate broadcast of GPG-encrypted messages -> https://github.com/shish/firehose https://github.com/shish/firehose
sillysaurus2 13y ago
I wonder why the common assumption is that the NSA doesn't run Tor nodes. Why wouldn't they? The NSA's (authorized) budget is $10.8 billion[1]. For $5 you can get a server with 20GB SSD and 1TB of transfer per month. It doesn't seem like it'd take very much money to be able to ensure that at least, say, 1% of Tor users' traffic passes through your entry and exit nodes, de-anonymizing them. So over a long enough time scale, that would de-anonymize quite a lot of interesting traffic, and interesting users. One solution is VPN over Tor. But the NSA claims they've cracked 30 VPN providers, and are focused on cracking the rest as soon as possible. That's a lot of compromised VPN providers. You could set up your own server and use that as a VPN, but if you pay with Bitcoin, then it's trivial to analyze the blockchain to tie your identity to the server, unless you use a tumbling service like bitcoinfog. But even if you manage to get a server set up anonymously, then what? You still would want to use VPN over Tor, since that's your best bet for privacy. But as soon as you get de-anonymized on Tor, that correlates your home IP address with your anonymous server, thus de-anonymizing your server too. I can't think of any options to be truly safe from a global passive adversary that doesn't also cost >1MM to set up initially. Any ideas? [1] http://www.washingtonpost.com/wp-srv/special/national/black-budget/ http://www.washingtonpost.com/wp-srv/special/national/black-...
- alexkus 13y ago
  > unless you use a tumbling service like bitcoinfog Which could be run by the NSA... It's turtles all of the way down.
- elorant 13y ago
  Connect to the Internet only through public WiFi hotspots. Run a sandboxed browser with all cookies deleted in each session or no cookies at all.
  - tmp3123 13y ago
    still can't avoid security cams + face recognition...
    - 13y ago
tokenizerrr 13y ago
I'm somewhat confused, exit nodes are not used when connecting to tor services, right? Only when you use tor to connect to the regular web.

aegiso 13y ago

So I'm totally making stuff up here, and my interest in crypto has a hackish rather than academic flavor, but... Couldn't we design a system that doesn't fall in this scenario, by using a constant-rate packet-blasting network that emits "background radiation" even if nothing is happening, and then filters out the good stuff via chaffing/winnowing [1]? This would clog the tubes like a torrent and run you a similar tab, but wouldn't it be 100% anonymous even in the face of such an adversary, while still being low-latency? [1] http://en.wikipedia.org/wiki/Chaffing_and_winnowing http://en.wikipedia.org/wiki/Chaffing_and_winnowing

sillysaurus2 13y ago
Yes, but Tor is already very slow, and it has a lot of resources behind it already. It would take a substantial amount of money to bootstrap your network. It'd be a worthy 1-10MM investment --- assuming you don't want any ROI on it.
simcop2387 13y ago
Freenet actually does this, though they aren't just sending random chaff, they'll actually use it to duplicate the data. It makes this particular attack impossible, but freenet has it's own potential issues. If you control all of someone's inputs and outputs you can still determine when they are using the system.
Shish2k 13y ago
I'm working on something along those lines at the moment - constant rate broadcast of GPG-encrypted messages -> https://github.com/shish/firehose https://github.com/shish/firehose

sillysaurus2 13y ago

I wonder why the common assumption is that the NSA doesn't run Tor nodes. Why wouldn't they? The NSA's (authorized) budget is $10.8 billion[1]. For $5 you can get a server with 20GB SSD and 1TB of transfer per month. It doesn't seem like it'd take very much money to be able to ensure that at least, say, 1% of Tor users' traffic passes through your entry and exit nodes, de-anonymizing them. So over a long enough time scale, that would de-anonymize quite a lot of interesting traffic, and interesting users. One solution is VPN over Tor. But the NSA claims they've cracked 30 VPN providers, and are focused on cracking the rest as soon as possible. That's a lot of compromised VPN providers. You could set up your own server and use that as a VPN, but if you pay with Bitcoin, then it's trivial to analyze the blockchain to tie your identity to the server, unless you use a tumbling service like bitcoinfog. But even if you manage to get a server set up anonymously, then what? You still would want to use VPN over Tor, since that's your best bet for privacy. But as soon as you get de-anonymized on Tor, that correlates your home IP address with your anonymous server, thus de-anonymizing your server too. I can't think of any options to be truly safe from a global passive adversary that doesn't also cost >1MM to set up initially. Any ideas? [1] http://www.washingtonpost.com/wp-srv/special/national/black-budget/ http://www.washingtonpost.com/wp-srv/special/national/black-...

alexkus 13y ago
> unless you use a tumbling service like bitcoinfog Which could be run by the NSA... It's turtles all of the way down.
elorant 13y ago
Connect to the Internet only through public WiFi hotspots. Run a sandboxed browser with all cookies deleted in each session or no cookies at all.
- tmp3123 13y ago
  still can't avoid security cams + face recognition...
  - 13y ago

tokenizerrr 13y ago

I'm somewhat confused, exit nodes are not used when connecting to tor services, right? Only when you use tor to connect to the regular web.