[guardian-dev] Key verification removed from TextSecure

[Hans-Christoph Steiner]

TOFU/POP is the model that ssh has used for years (how many people actually
validate the fingerprints?).  POP is a key part of the idea: Persistence of
Pseudonym.  When you accept a key, you're creating a pseudonym, so the other
half of that model is keeping that pseudonym ID around to validate agaisnt.

.hc

On 05/31/2013 06:33 AM, Bernard Tyers - ei8fdb wrote:
> What is the implications for the security and verification of the users SMS in this case?
> 
> To me that seems like: if the initial SMS is bogus, then the rest of the conversation can be bogus?
> 
> Is there any idea of the reasoning for this change? Technical, commercial?
> 
> I guess overall: how more or less secure is the user because of this change?
> 
> 
> The only information I can find on TOFU (TUFU) is:
> 
> http://en.wikipedia.org/wiki/User:Dotdotike/Trust_Upon_First_Use
> http://defcon.org/html/defcon-18/dc-18-speakers.html#
> http://static.usenix.org/events/usenix08/tech/full_papers/wendlandt/wendlandt_html/index.html
> 
> anyone got any other info?
> 
> thanks,
> Bernard
> 
> 
> On 31 May 2013, at 00:07, Abel Luck wrote:
> 
>> TextSecure no longer supports the concept of "verified" and
>> "unverified", instead Moxie has moved to this concept of an identity key
>> combined with TOFU POP.
> 
>> "There is no longer a concept of "verified" or "unverified."
>>   Only "what we saw last time" and "different from last time."
>> See:
>> https://github.com/WhisperSystems/TextSecure/commit/24fc93e9aeb5d0810eb9c7e7d79da019b84035f5
> 
>> ~abel
> 
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> --------------------------------------
> Bernard / bluboxthief / ei8fdb
> 
> IO91XM / www.ei8fdb.org
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