[messaging] Password reset mechanisms with an SRP authentication framework

[Trevor Perrin]

On Tue, Apr 22, 2014 at 12:11 PM, Michael Rogers
<michael at briarproject.org> wrote:
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> On 22/04/14 19:47, Trevor Perrin wrote:
>>> * The friends don't have enough shares to reconstruct the key
>>> even if they collude
>>
>> They do, if n-2 >= k.
>
> Doh, sorry, I tried to generalise this from k=4, n=5 and failed. :0)
> The user should keep n-k+1 shares on her device.

Still doesn't seem right.  I think you're trying to accomplish:
 (a) The user has a key which is required for recovery
 (b) A quorum of friends is also required for recovery

I think this is better implemented by setting the final key to an XOR
of the keys recovered from (a) and (b).


Trevor