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> The various journalists involved will not send the data over the internet for obvious reasons - even if encrypted, it allows the various agencies know who has

> The various journalists involved will not send the data over the internet for obvious reasons - even if encrypted, it allows the various agencies know who has what. Question out of my ignorance: couldn't the Tor network obfuscate such things sufficiently?

ealexhudson 13y ago
I suppose "sufficiently" is indeed the question. If the NSA own enough of the end points they can see the data coming in and out again. Snowden said encryption was good enough to keep data private, but perhaps he also believes Tor isn't good enough to keep usage anonymous.
- crazypyro 13y ago
  What about PGP or other encryption? Surely, the NSA couldn't crack a PGP encrypted message sent over tor, could they? (Assuming no access to private keys) Disclaimer: I have basic understanding of security, but not much more.
- cryptart 13y ago
  Tor, as a low-latency mix-net, is known to be vulnerable to a large-scale traffic analysis. However, I'm not sure exactly why the parties involved actually need anonymity -- everyone knows that Greenwald is in communication with Poitras. If the point is to shield the data from size analysis, couldn't they use padding? Of course, these are journalists and not engineers. Maybe what they need is a team of IT/crypto consultants. Surely there would be plenty of volunteers.
papaf 13y ago
Many papers on anonymous networks talk about a global passive adversary that has access to the data entering and leaving every node. Very few of the papers that I have read claim their networks are effective against a global passive adversary (GPA). The ones that do claim to be effective, and back that up with some calculations of entropy, are really inefficient. I don't think Tor ever claimed to be effective against a GPA. This paper gives some background: http://mice.cs.columbia.edu/getTechreport.php?techreportID=556&format=pdf& http://mice.cs.columbia.edu/getTechreport.php?techreportID=5...

ealexhudson 13y ago

I suppose "sufficiently" is indeed the question. If the NSA own enough of the end points they can see the data coming in and out again. Snowden said encryption was good enough to keep data private, but perhaps he also believes Tor isn't good enough to keep usage anonymous.

crazypyro 13y ago
What about PGP or other encryption? Surely, the NSA couldn't crack a PGP encrypted message sent over tor, could they? (Assuming no access to private keys) Disclaimer: I have basic understanding of security, but not much more.
cryptart 13y ago
Tor, as a low-latency mix-net, is known to be vulnerable to a large-scale traffic analysis. However, I'm not sure exactly why the parties involved actually need anonymity -- everyone knows that Greenwald is in communication with Poitras. If the point is to shield the data from size analysis, couldn't they use padding? Of course, these are journalists and not engineers. Maybe what they need is a team of IT/crypto consultants. Surely there would be plenty of volunteers.

papaf 13y ago

Many papers on anonymous networks talk about a global passive adversary that has access to the data entering and leaving every node. Very few of the papers that I have read claim their networks are effective against a global passive adversary (GPA). The ones that do claim to be effective, and back that up with some calculations of entropy, are really inefficient. I don't think Tor ever claimed to be effective against a GPA. This paper gives some background: http://mice.cs.columbia.edu/getTechreport.php?techreportID=556&format=pdf& http://mice.cs.columbia.edu/getTechreport.php?techreportID=5...