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From the open letter on http://technosociology.org/?page_id=1687 http://technosociology.org/?page_id=1687 : > The behavior described in your article is not a b

From the open letter on http://technosociology.org/?page_id=1687 http://technosociology.org/?page_id=1687 : > The behavior described in your article is not a backdoor in WhatsApp. This is the overwhelming consensus of the cryptography and security community. It is also the collective opinion of the cryptography professionals whose names appear below. The behavior you highlight is a measured tradeoff that poses a remote threat in return for real benefits that help keep users secure, as we will discuss in a moment. What real benefits are gained from making it easy for ISP-level attackers to mount man-in-the-middle attacks? Security from your spouse snooping on your phone? What's the threat model here and why are these experts so adamant in minimizing the security risks? Moxie went as far as to ignore the opt-in aspect of the (very benign looking) key change notification, but he's on the payroll. What's the motivation of the other experts in this sudden "overwhelming consensus"?

maxerickson 10y ago
Some of the motivation is that users who need security tend to switch sims fairly often. If the messaging system doesn't deliver messages when that happens, they will stop using it.
- stefantalpalaru 10y ago
  Switching SIMs means switching accounts, because phone numbers are usernames, right? Why would the application hide this by default? Also, why would the key change be hidden by default when the phone number doesn't change? This is the actual mechanism described by Tobias Boelter in his report: https://tobi.rocks/2016/04/whats-app-retransmission-vulnerability/ https://tobi.rocks/2016/04/whats-app-retransmission-vulnerab... Is this done to facilitate the "same SIM, lost local storage" scenario? Then the phone number is not only username but also a password and anybody able to steal the phone (or just the number) can impersonate a WhatsApp user. Is this the level of security these experts are protecting?
tptacek 10y ago
The open letter answers your question. I'll flip it around on you: what makes you think you're seeing some important wrinkle of this problem that Matthew Green, Bruce Schneier, Matt Blaze, Steve Checkoway, Chris Palmer, Dave Adrian, Bart Preneel, Jonathan Zdziarski, Steve Bellovin, and Emin Gür Sirer aren't seeing? Many of these people study backdoors, and crypto backdoors in particular, practically full-time.
- baybal2 10y ago
  >Matthew Green, Bruce Schneier, Matt Blaze, Steve Checkoway, Chris Palmer, Dave Adrian, Bart Preneel, Jonathan Zdziarski, Steve Bellovin, and Emin Gür Sirer. Some assorted bloggers and amateur cryptographers with big mouths and no serious crypto/math background like whom probably you are. Their opinion worth not.
  - tedunangst 10y ago
    A true gem of a comment.
  - Analemma_ 10y ago
    You have no idea what you're talking about.
  - rockdoe 10y ago
    The weird thing is that these days it's impossible to tell whether that was an ironic post or not.
- stefantalpalaru 10y ago
  > what makes you think you're seeing some important wrinkle of this problem that Matthew Green, Bruce Schneier, Matt Blaze, Steve Checkoway, Chris Palmer, Dave Adrian, Bart Preneel, Jonathan Zdziarski, Steve Bellovin, and Emin Gür Sirer aren't seeing? The fact that you sound like activists instead of experts. I get it, Zeynep Tufekci convinced all of you that "freedom fighters" within the Gülen movement are in danger of switching to SMS and getting imprisoned, tortured and killed so you're panicking and asking for The Guardian to make an article disappear. This attitude is not professional, though. I don't care that you all think that only the "good guys" have the capacity to pull off the man-in-the-middle attack using the exposed vulnerability. Sooner or later, the Turkish government (that controls ISPs) will figure out how to do it too and even the well-meaning armchair activist will get a few drops of blood on their hands. You failed when you gave up everything you knew about security through obscurity and threat modelling just because you were startled by the plural of anecdote (how did you call it? empirical evidence?). You failed when you started to say that a backdoor is not a backdoor because you wanted so bad for mainstream end-to-end encryption to make everybody secure by default. Even if it's just security theatre right now. You failed, Ptacek, just like Schneier failed when he started to support the "Russia hacked the DNC" story when there was no evidence for it. Maybe in time you'll learn to practice what you preach and develop some sort of professional ethics.
tedunangst 10y ago
Don't you just hate it when everybody else is wrong and you're the only person who's right?

maxerickson 10y ago

Some of the motivation is that users who need security tend to switch sims fairly often. If the messaging system doesn't deliver messages when that happens, they will stop using it.

stefantalpalaru 10y ago
Switching SIMs means switching accounts, because phone numbers are usernames, right? Why would the application hide this by default? Also, why would the key change be hidden by default when the phone number doesn't change? This is the actual mechanism described by Tobias Boelter in his report: https://tobi.rocks/2016/04/whats-app-retransmission-vulnerability/ https://tobi.rocks/2016/04/whats-app-retransmission-vulnerab... Is this done to facilitate the "same SIM, lost local storage" scenario? Then the phone number is not only username but also a password and anybody able to steal the phone (or just the number) can impersonate a WhatsApp user. Is this the level of security these experts are protecting?

tptacek 10y ago

The open letter answers your question. I'll flip it around on you: what makes you think you're seeing some important wrinkle of this problem that Matthew Green, Bruce Schneier, Matt Blaze, Steve Checkoway, Chris Palmer, Dave Adrian, Bart Preneel, Jonathan Zdziarski, Steve Bellovin, and Emin Gür Sirer aren't seeing? Many of these people study backdoors, and crypto backdoors in particular, practically full-time.

baybal2 10y ago
>Matthew Green, Bruce Schneier, Matt Blaze, Steve Checkoway, Chris Palmer, Dave Adrian, Bart Preneel, Jonathan Zdziarski, Steve Bellovin, and Emin Gür Sirer. Some assorted bloggers and amateur cryptographers with big mouths and no serious crypto/math background like whom probably you are. Their opinion worth not.
- tedunangst 10y ago
  A true gem of a comment.
- Analemma_ 10y ago
  You have no idea what you're talking about.
- rockdoe 10y ago
  The weird thing is that these days it's impossible to tell whether that was an ironic post or not.
stefantalpalaru 10y ago
> what makes you think you're seeing some important wrinkle of this problem that Matthew Green, Bruce Schneier, Matt Blaze, Steve Checkoway, Chris Palmer, Dave Adrian, Bart Preneel, Jonathan Zdziarski, Steve Bellovin, and Emin Gür Sirer aren't seeing? The fact that you sound like activists instead of experts. I get it, Zeynep Tufekci convinced all of you that "freedom fighters" within the Gülen movement are in danger of switching to SMS and getting imprisoned, tortured and killed so you're panicking and asking for The Guardian to make an article disappear. This attitude is not professional, though. I don't care that you all think that only the "good guys" have the capacity to pull off the man-in-the-middle attack using the exposed vulnerability. Sooner or later, the Turkish government (that controls ISPs) will figure out how to do it too and even the well-meaning armchair activist will get a few drops of blood on their hands. You failed when you gave up everything you knew about security through obscurity and threat modelling just because you were startled by the plural of anecdote (how did you call it? empirical evidence?). You failed when you started to say that a backdoor is not a backdoor because you wanted so bad for mainstream end-to-end encryption to make everybody secure by default. Even if it's just security theatre right now. You failed, Ptacek, just like Schneier failed when he started to support the "Russia hacked the DNC" story when there was no evidence for it. Maybe in time you'll learn to practice what you preach and develop some sort of professional ethics.

tedunangst 10y ago

Don't you just hate it when everybody else is wrong and you're the only person who's right?