10 ms·

Laura Poitras on the Crypto Tools That Made Her Snowden Film Possible

99 points by antimora 12y ago

s_q_b 12y ago
Comforting to see my own privacy stack is almost exactly the same: Tails running specially configured Tor (five hop circuit, permanent guard nodes, and routes through countries unlikely to cooperate with one another), GPG for email, OTR for IM, Signal for mobile, and True Crypt + Apple disk encryption. Funny thing is, I don't even have any particular use for it other than kicking around vulnerability and security discussions with friends and colleagues that I highly doubt anyone is even trying to intercept. But it is very comforting to know that it's the same set of tools relied upon by those with something highly significant at stake.
- hellbanner 12y ago
  Do you run those nodes you hop through? Also.. congrats on finding people to communicate with securely-as-possible.
  - s_q_b 12y ago
    Thanks, it's mostly security nuts like me about security related topics. Hopping through my own Tor nodes could be a bit counter-productive, as it would make attribution of my circuit quite a bit easier. I use an extended hop relay with hand-selected nodes, which allows me to use five hops instead of the standard three, and hand-select fast relays that are in nations which are unlikely to share information readily. There's a few more tricks I use to counter e.g. stream watermarking, but at a certain point you reach diminishing returns, as the browser is only so secure. If I was running a drug cartel, it'd be appropriate COMSEC, but for me its really more of an experiment than anything else.
    - trebla 12y ago
      Well, there are many uses. Impopular speech is in theory protected by free speech laws, but in practice you are only safe doing popular speech. Anyone that says something impopular should use COMSEC. It might not be needed today, but I'd use it to be safe tomorrow.
      - s_q_b 12y ago
        Free speech is an ideal I hold closely, and I would rather let myself be locked up, with all that entails, than acquiesce to governance that required I renounce it. So if I no longer live in a country that feels as I do, which I very sincerely doubt, let come what may.
    - s_q_b 12y ago
      @tor_user, your comment is dead, but since I have showdead on: I go beyond the .torrc config settings. I have a custom Python controller that uses Stem[0] to interface with the tor binary's control port to build my paths and circuits. My tor binary has some customizations as well (stop sending 512 byte cells by default, random packet delays with large transfers, creative TLS and circuit multiplexing), and of course there's the standard use of obfsproxy[1], unlisted bridges[2], etc. [0]https://stem.torproject.org/ https://stem.torproject.org/ [1]https://www.torproject.org/projects/obfsproxy.html.en https://www.torproject.org/projects/obfsproxy.html.en [2]https://bridges.torproject.org/ https://bridges.torproject.org/
- acconrad 12y ago
  How do you use these things in the wild? Privacy stacks generally require that they are installed on both ends of the message. Trying to get my friends and family to exchange encrypted texts or OTR IMs is basically impossible.
  - tP5n 12y ago
    Encrypted text messages are relatively easy to implement as the apps (textsecure/redphone - signal) in question 'stack' nicely on top of whatever they were using for SMS already. Encrypted mails are more problematic but aslong as they are using web mail, get them Mailvelope. On android with the K9 mailclient (+ openkeychain/apg) PGP-inline is possible to use, while it's not something your 'friends and family' will enjoy. I have a personal disdain for pidgin/adium (libpurple), but similar to encrypted text messages: Once setup OTR is out of the way of your standard IM usage and it comes down to understanding user authentication.
    - s_q_b 12y ago
      Tor's transparent and only my problem, Signal is easy to set up for laymen, GPGTools isn't hard to walk through (I know attorneys that use it just fine), OTR has plugins for everything that supports XMPP...
- tor_user 12y ago
  1. How do you configure tor to use more than three hops? It's not in the manual [1]. 2. Do you only use the EntryNodes, ExitNodes and ExcludeNodes to shape the Tor path (country to country), or something else? Working on an open source project that could benefit. Thanks! [1] https://www.torproject.org/docs/tor-manual.html.en https://www.torproject.org/docs/tor-manual.html.en
- iwwr 12y ago
  >five hop circuit, permanent guard nodes, and routes through countries unlikely to cooperate with one another Won't that make your circuits more predictible as a consequence?
  - domenzain 12y ago
    Assuming not all the machines are compromised, the longer the path, the less likely any agent is to follow it along in its entirety. Even if the whole path were compromised (but by different antagonistic parties) this would still hold.
  - s_q_b 12y ago
    To add to what was said, the only one of those measures that's potentially dangerous is the single guard node with manual rotation. It's not adequately studied, and I'm operating based upon my own research and intuition there, so I wouldn't necessarily recommend it.
diminoten 12y ago
Oh hey look, TrueCrypt. Despite the more vocal members of the security industry basically hating the software, it turns out to be one of the few tools folks have successfully used to maintain their privacy.
- tedunangst 12y ago
  Did it? Seems like a claim that could use some elaboration. In what way would her privacy have been compromised by not using truecrypt? How do we know her privacy wasn't compromised despite using truecrypt?
  - diminoten 12y ago
    The same way we know unicorns aren't real -- we have no evidence to think so.
    - noinsight 12y ago
      Absence of evidence is not evidence of absence.
      - patzerhacker 12y ago
        Those making claims are required to produce the evidence for their claims. Nobody is ever required to prove a negative. That's not how logic works.
      - tptacek 12y ago
        Greenwald and Snowden also used Cryptocat in Q1 2013. Now, there's no evidence to think that NSA decrypted all those messages... but in Q1 2013, Cryptocat was breakable; by NSA in June, and by anyone with a laptop from May all the way back to October 2011. These attacks are passive. If you've been hoovering up all the raw Internet traffic, you can go back through your archives and decrypt all the Cryptocat traffic from those time periods. So my point being, when your adversaries are nations, there usually isn't going to be "evidence" that your comms were decrypted, at least not until you're indicted. You're right: that doesn't mean it didn't happen. I don't think anything interesting happened with Truecrypt, though.

99 points by antimora 12y ago

s_q_b 12y ago

Comforting to see my own privacy stack is almost exactly the same: Tails running specially configured Tor (five hop circuit, permanent guard nodes, and routes through countries unlikely to cooperate with one another), GPG for email, OTR for IM, Signal for mobile, and True Crypt + Apple disk encryption. Funny thing is, I don't even have any particular use for it other than kicking around vulnerability and security discussions with friends and colleagues that I highly doubt anyone is even trying to intercept. But it is very comforting to know that it's the same set of tools relied upon by those with something highly significant at stake.

hellbanner 12y ago
Do you run those nodes you hop through? Also.. congrats on finding people to communicate with securely-as-possible.
- s_q_b 12y ago
  Thanks, it's mostly security nuts like me about security related topics. Hopping through my own Tor nodes could be a bit counter-productive, as it would make attribution of my circuit quite a bit easier. I use an extended hop relay with hand-selected nodes, which allows me to use five hops instead of the standard three, and hand-select fast relays that are in nations which are unlikely to share information readily. There's a few more tricks I use to counter e.g. stream watermarking, but at a certain point you reach diminishing returns, as the browser is only so secure. If I was running a drug cartel, it'd be appropriate COMSEC, but for me its really more of an experiment than anything else.
  - trebla 12y ago
    Well, there are many uses. Impopular speech is in theory protected by free speech laws, but in practice you are only safe doing popular speech. Anyone that says something impopular should use COMSEC. It might not be needed today, but I'd use it to be safe tomorrow.
    - s_q_b 12y ago
      Free speech is an ideal I hold closely, and I would rather let myself be locked up, with all that entails, than acquiesce to governance that required I renounce it. So if I no longer live in a country that feels as I do, which I very sincerely doubt, let come what may.
  - s_q_b 12y ago
    @tor_user, your comment is dead, but since I have showdead on: I go beyond the .torrc config settings. I have a custom Python controller that uses Stem[0] to interface with the tor binary's control port to build my paths and circuits. My tor binary has some customizations as well (stop sending 512 byte cells by default, random packet delays with large transfers, creative TLS and circuit multiplexing), and of course there's the standard use of obfsproxy[1], unlisted bridges[2], etc. [0]https://stem.torproject.org/ https://stem.torproject.org/ [1]https://www.torproject.org/projects/obfsproxy.html.en https://www.torproject.org/projects/obfsproxy.html.en [2]https://bridges.torproject.org/ https://bridges.torproject.org/
acconrad 12y ago
How do you use these things in the wild? Privacy stacks generally require that they are installed on both ends of the message. Trying to get my friends and family to exchange encrypted texts or OTR IMs is basically impossible.
- tP5n 12y ago
  Encrypted text messages are relatively easy to implement as the apps (textsecure/redphone - signal) in question 'stack' nicely on top of whatever they were using for SMS already. Encrypted mails are more problematic but aslong as they are using web mail, get them Mailvelope. On android with the K9 mailclient (+ openkeychain/apg) PGP-inline is possible to use, while it's not something your 'friends and family' will enjoy. I have a personal disdain for pidgin/adium (libpurple), but similar to encrypted text messages: Once setup OTR is out of the way of your standard IM usage and it comes down to understanding user authentication.
  - s_q_b 12y ago
    Tor's transparent and only my problem, Signal is easy to set up for laymen, GPGTools isn't hard to walk through (I know attorneys that use it just fine), OTR has plugins for everything that supports XMPP...
tor_user 12y ago
1. How do you configure tor to use more than three hops? It's not in the manual [1]. 2. Do you only use the EntryNodes, ExitNodes and ExcludeNodes to shape the Tor path (country to country), or something else? Working on an open source project that could benefit. Thanks! [1] https://www.torproject.org/docs/tor-manual.html.en https://www.torproject.org/docs/tor-manual.html.en
iwwr 12y ago
>five hop circuit, permanent guard nodes, and routes through countries unlikely to cooperate with one another Won't that make your circuits more predictible as a consequence?
- domenzain 12y ago
  Assuming not all the machines are compromised, the longer the path, the less likely any agent is to follow it along in its entirety. Even if the whole path were compromised (but by different antagonistic parties) this would still hold.
- s_q_b 12y ago
  To add to what was said, the only one of those measures that's potentially dangerous is the single guard node with manual rotation. It's not adequately studied, and I'm operating based upon my own research and intuition there, so I wouldn't necessarily recommend it.

diminoten 12y ago

Oh hey look, TrueCrypt. Despite the more vocal members of the security industry basically hating the software, it turns out to be one of the few tools folks have successfully used to maintain their privacy.

tedunangst 12y ago
Did it? Seems like a claim that could use some elaboration. In what way would her privacy have been compromised by not using truecrypt? How do we know her privacy wasn't compromised despite using truecrypt?
- diminoten 12y ago
  The same way we know unicorns aren't real -- we have no evidence to think so.
  - noinsight 12y ago
    Absence of evidence is not evidence of absence.
    - patzerhacker 12y ago
      Those making claims are required to produce the evidence for their claims. Nobody is ever required to prove a negative. That's not how logic works.
    - tptacek 12y ago
      Greenwald and Snowden also used Cryptocat in Q1 2013. Now, there's no evidence to think that NSA decrypted all those messages... but in Q1 2013, Cryptocat was breakable; by NSA in June, and by anyone with a laptop from May all the way back to October 2011. These attacks are passive. If you've been hoovering up all the raw Internet traffic, you can go back through your archives and decrypt all the Cryptocat traffic from those time periods. So my point being, when your adversaries are nations, there usually isn't going to be "evidence" that your comms were decrypted, at least not until you're indicted. You're right: that doesn't mean it didn't happen. I don't think anything interesting happened with Truecrypt, though.