Seems pretty good overall. The only primary bullet point to "fail" was here:
>In conclusion, TEXTSECURE only achieves deniability
theoretically. Content deniability is provided due to our
security proof but we can not prove that no delivery request will be recorded at the TEXTSECURE server.
I would like to see a tool, perhaps even a companion app, that does this HMAC gymnastics to prior discussions to make deniability actually plausible instead of just theoretically plausible.
"Your honor, the defendant is clearly not Moxie Marlinspike. She said these things." "Objection! My grandmother can use Axylnotly to forge previous discussion and she is also not Moxie Marlinspike." " ... sustained."
> This type of score card drastically simplifies the problem domain, and leads one to question what the tradeoffs are when installing an application from the list. While the advocacy of privacy based communication is something we love to see reach a mainstream audience, we believe the scorecard misses many considerations and metrics that are critical to the discussion.
To quote myself:
> The EFF score card is an embarrassment which is essentially equivalent to one of those "comparison table of our competitors" on a SaaS website. That's a good analogy for it, because it uses the same questionable metrics and even more questionable ranking system that one of those tables would use. The score card gives Signal the same ranking as Cryptocat - that's an instant negative result for its usefulness.
I agree. I particularly like your emphasis in last discussion on fact that they "buried PGP." PGP and then GPG have a long history of working against most powerful of the nation-state hackers. The Snowden leaks feature NSA smashing almost everything except for a rare few you can count on one hand IIRC. One of those is GPG. "NSA-proof in 2013" should get put next to its name on top of list, bolded, highlighted, etc.
Curious, what do you think of the worth of a LibreSSL-style effort to clean up GPG's proven code and build better interfaces for integrating it into other apps? Of course, to be done in parallel with development of things like Signal that will get more adoption.
The TextSecure protocol is now named the "Signal Protocol"; it's developed by Open Whisper Systems. It is the protocol used by the Signal app on Android and iPhone, and as of this week, also used by WhatsApp.
The main takeaway: text messaging, unlike traditional instant messaging, is primarily asynchronous with long-lived sessions, where traditional instant messaging is primarily synchronous with short-lived sessions.
Do you happen to know whether this is the same protocol used in SMSSecure? I know it is a fork of TextSecure but am not clear on whether TextSecure changed their protocol after the fork in the process of becoming Signal.
> Furthermore, we formally prove that - if key registration is assumed to be secure - TextSecure's push messaging can indeed achieve most of the claimed security goals.
The mayor issue IMHO is the dependency to Google Cloud Messenger as the only available push notification system for android devices and its dependency to Google Play store. I believe an actor as powerfull as Google can detect paterns and learn from the notifications it handles even if the text is encrypted.
22 comments
[ 7.3 ms ] story [ 58.1 ms ] thread> Date: received 31 Oct 2014, last revised 5 Apr 2016
[0] https://news.ycombinator.com/item?id=8544814
>In conclusion, TEXTSECURE only achieves deniability theoretically. Content deniability is provided due to our security proof but we can not prove that no delivery request will be recorded at the TEXTSECURE server.
"Your honor, the defendant is clearly not Moxie Marlinspike. She said these things." "Objection! My grandmother can use Axylnotly to forge previous discussion and she is also not Moxie Marlinspike." " ... sustained."
> This type of score card drastically simplifies the problem domain, and leads one to question what the tradeoffs are when installing an application from the list. While the advocacy of privacy based communication is something we love to see reach a mainstream audience, we believe the scorecard misses many considerations and metrics that are critical to the discussion.
To quote myself:
> The EFF score card is an embarrassment which is essentially equivalent to one of those "comparison table of our competitors" on a SaaS website. That's a good analogy for it, because it uses the same questionable metrics and even more questionable ranking system that one of those tables would use. The score card gives Signal the same ranking as Cryptocat - that's an instant negative result for its usefulness.
Curious, what do you think of the worth of a LibreSSL-style effort to clean up GPG's proven code and build better interfaces for integrating it into other apps? Of course, to be done in parallel with development of things like Signal that will get more adoption.
Here is an older post where the authors of the protocol explain why not OTR: https://whispersystems.org/blog/advanced-ratcheting/
The main takeaway: text messaging, unlike traditional instant messaging, is primarily asynchronous with long-lived sessions, where traditional instant messaging is primarily synchronous with short-lived sessions.