Hi Marcela,

Thanks so much for the quick reply!

> I'm assuming you mean Alice is the user with the strict key change policy in 
> this example? So yes, Alice's client would see the strict flag set as part of 
> Alice's user metadata and would know to cache Bob's key and only accept a new 
> one if the key change is authenticated with the cached key.


Well, I meant that Bob has the strict policy set, and that Alice sees that and 
therefore only accepts a new key from Bob if it’s signed by his previous key. 
But your answer seems to also apply to Bob?

> Right, the specification of the key change protocol was actually a follow-up 
> project I worked on with an undergraduate, who wrote his junior research 
> paper on it. He also implemented this protocol, and getting it merged into 
> our reference implementation on GitHub is in the works. In the meantime, I 
> can get his junior paper on the CONIKS website.

Yes that would be great, I'd very much like to read that. :-)

> There is, you can sign up at coniks.cs.princeton.edu

Thanks! I’ve signed up! ^_^

Cheers,
Greg

> On Mar 21, 2016, at 11:35 PM, Marcela S. Melara <[email protected]> 
> wrote:
> 
> Hi Greg
> 
>> On Mar 21, 2016, at 22:56, Tao Effect <[email protected]> wrote:
>> 
>> Dear list,
>> 
>> Questions for Joseph, Marcela, or any other CONIKS experts out there:
>> 
>> Regarding the strict key change policy mentioned in the paper, how can Alice 
>> verify Bob’s latest key? Does she cache his previous key and verify the 
>> latest one received comes with a key-change message that’s signed by the 
>> previously cached key?
> 
> I'm assuming you mean Alice is the user with the strict key change policy in 
> this example? So yes, Alice's client would see the strict flag set as part of 
> Alice's user metadata and would know to cache Bob's key and only accept a new 
> one if the key change is authenticated with the cached key.
> 
>> This aspect doesn't seem to be part of the protocol described in the paper. 
>> If there is a way to securely verify the key change using a previously 
>> verified/pinned key then this mechanism could prevent MITM attacks.
>> So is this specified in an “official protocol” somewhere?
> 
> Right, the specification of the key change protocol was actually a follow-up 
> project I worked on with an undergraduate, who wrote his junior research 
> paper on it. He also implemented this protocol, and getting it merged into 
> our reference implementation on GitHub is in the works. In the meantime, I 
> can get his junior paper on the CONIKS website.
> 
>> Also, is there an official discussion list for CONIKS?
> 
> There is, you can sign up at coniks.cs.princeton.edu
> 
>> 
>> Thanks much!
>> Greg
>> _______________________________________________
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>> https://moderncrypto.org/mailman/listinfo/messaging

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