[liberationtech] Peer-review required: SwaTwt and TweedleDH

[Steve Weis]

Besides the fact that this is asking users to trust "SwaTwt.com"
completely, the underlying crypto algorithm is "CipherSaber 2". That
appears to be a variant of RC4 of dubious origins and quality. Even if
this were a good algorithm choice, the implementation itself is
insecure. Here's a hint:
http://github.com/thedod/SwaTwt/blob/master/index.html#L161

This is a bad design, bad algorithm, and bad implementation. Do not
use it for anything you wish to keep secret.

On Tue, Sep 28, 2010 at 10:52 AM, Uncle "The Dod" Zzzen
<unclezzzen at gmail.com> wrote:
> I've lately developed 2 nomadic-crypto tools (based on 2002 work by
> magaf.org RIP):
>
> * SwaTwt (sealed with a Tweet) - symmetric encryption in JavaScript,
> with pastebin and [optional] Twitter integration.
> Source: http://github.com/thedod/SwaTwt
> Working site: http://SwaTwt.com
>
> * TwiddleDH - a desktop app for creating a shared secret with a peer
> (Diffie-Hellman key exchange) over IM or Twitter.
> Source: http://github.com/thedod/tweedledh/
>
> There's also a tutorial at http://j.mp/privacy4dummies
>
> Goals:
> 1) The system tries to be as nomadic as possible: zero installation for
> SwaTwt, zero configuration for TweedleDH, no keys are stored. It tries
> to keep the code small and simple enough for review (no binaries - of
> course).
>
> 2) It also tries to address laypeople. Now that is a risky thing to do,
> since - as Bruce Schnier says - "If you think technology can solve your
> security problems, then you don't understand the problems and you don't
> understand the technology". Still - the goal should be that any sensible
> person who reads the documentation would be able use all this rope
> without ending up hanging from it. We can expect some people not to use
> the system wisely, but they also contribute to the signal-to-noise
> ratio :) On the other hand - the documentation shouldn't be
> prohibitively long or too complicated. Bottom line - feedback on
> documentation (or alternative documentation) is especially important in
> this case.
>
> 3) Another goal of the system is integration with twitter (although you
> can use it for one-on-one communication over IM without worrying about
> all this). One of the reasons is not to pursue joindiaspora's idea of
> making an alternative to an existing social network (facebook), but to
> provide an 3rd party tool (like twitpic or twitlonger) to solve a small
> ad-hoc need. Less code, less bugs, less configuration errors, less
> vulnerabilities. SwaTwt does a lot less than what diaspora intends to do
> (the day my mom gets to run a node on *her* PC), but it runs on my cheap
> J2ME phone today.
>
> There's a lot of experimenting to be done with this unstable mixture of
> privacy and social networking, and it's bound to produce leaks (of
> secrets and even keys), but we need (both as individuals and as
> societies) to learn these skills, and to restore the privacy awareness
> socnet moguls keep urging us to forget.
>
> Cheers,
> Nimrod @TheRealDod Kerrett,
> Thailand
>
>
> _______________________________________________
> liberationtech mailing list
> liberationtech at lists.stanford.edu
>
> Should you need to change your subscription options, please go to:
>
> https://mailman.stanford.edu/mailman/listinfo/liberationtech
>