[messaging] Axolotl questions

[Trevor Perrin]

On Mon, Dec 15, 2014 at 1:03 PM, Sunny Marueli <sunnym at gmail.com> wrote:
>
> I was thinking about something like this:
>
> if ratchet_flag:
>   DHRs = generateECDH()
>   RK = HASH( DH(A, DHRr) || DH(DHRs, B) || DH(DHRs, DHRr) )
>   ratchet_flag = False

The long-term keys have already been used to agree on the root key.
Why perform frequent extra DHs to re-authenticate them, instead of
just using the root key?

Trevor