3 ms·

what's showily bad about Jabber + OTR? Kind of curious, I know there are security issues with older OTR versions but is there a known weakness in v3?

tptacek 10y ago
Not the Jabber/OTR thing. The decentralized nature of Jabber was pretty overblown, more something she wanted to be true and meaningful than something that actually was meaningful, but: whatever, it's 2011 at that point. It's the OpenSSL command line that I'm taking issue with.
- tricolon 10y ago
  In the interest of learning, what's the issue with the OpenSSL command?
  - tptacek 10y ago
    First, don't encrypt things directly with OpenSSL. Second, they're using unauthenticated AES-CBC, so an attacker that knows what file format they're sending can flip bits to exploit bugs and pop calc.exe on them. Third, reprising the first problem: using OpenSSL to encrypt means you're using OpenSSL's weak password KDF. In fact, I think the defaults when they were using this were single-iteration hash KDF; essentially: salted hashes. This is like the one application where GPG actually still makes sense to use, and GPG is easier to use here than OpenSSL in addition to being safer. OBVIOUSLY NONE OF THIS MATTERS. My issue with the article isn't "it recommends weak crypto". My issue is that despite the title, it isn't actually about crypto or surveillance or anything like that.
    - caf 10y ago
      It's just a poetic title - Love in the Time of Cholera isn't about epidemiology either.
    - gsylvie 10y ago
      The article does this: > openssl aes-256-cbc -a -salt -in for-you.mp3 -out for-you.mp3.enc Here's the KDF for that (in PHP): $round1 = hex2bin(md5($pwd . $salt)); $round2 = hex2bin(md5($round1 . $pwd . $salt)); $round3 = hex2bin(md5($round2 . $pwd . $salt)); $key = $round1 . $round2; $iv = $round3; It still defaults to that (I'm on Ubuntu 16.04): $ openssl version OpenSSL 1.0.2g 1 Mar 2016
      - tptacek 10y ago
        Ow.

tptacek 10y ago

Not the Jabber/OTR thing. The decentralized nature of Jabber was pretty overblown, more something she wanted to be true and meaningful than something that actually was meaningful, but: whatever, it's 2011 at that point. It's the OpenSSL command line that I'm taking issue with.

tricolon 10y ago
In the interest of learning, what's the issue with the OpenSSL command?
- tptacek 10y ago
  First, don't encrypt things directly with OpenSSL. Second, they're using unauthenticated AES-CBC, so an attacker that knows what file format they're sending can flip bits to exploit bugs and pop calc.exe on them. Third, reprising the first problem: using OpenSSL to encrypt means you're using OpenSSL's weak password KDF. In fact, I think the defaults when they were using this were single-iteration hash KDF; essentially: salted hashes. This is like the one application where GPG actually still makes sense to use, and GPG is easier to use here than OpenSSL in addition to being safer. OBVIOUSLY NONE OF THIS MATTERS. My issue with the article isn't "it recommends weak crypto". My issue is that despite the title, it isn't actually about crypto or surveillance or anything like that.
  - caf 10y ago
    It's just a poetic title - Love in the Time of Cholera isn't about epidemiology either.
  - gsylvie 10y ago
    The article does this: > openssl aes-256-cbc -a -salt -in for-you.mp3 -out for-you.mp3.enc Here's the KDF for that (in PHP): $round1 = hex2bin(md5($pwd . $salt)); $round2 = hex2bin(md5($round1 . $pwd . $salt)); $round3 = hex2bin(md5($round2 . $pwd . $salt)); $key = $round1 . $round2; $iv = $round3; It still defaults to that (I'm on Ubuntu 16.04): $ openssl version OpenSSL 1.0.2g 1 Mar 2016
    - tptacek 10y ago
      Ow.