[noise] Additional 0-RTT modes

[Trevor Perrin]

On Tue, Aug 1, 2017 at 7:28 PM, Trevor Perrin <trevp at trevp.net> wrote:
>
> In any case, we can provide a PSK option by deriving resumption PSKs
> from an initial connection.  To give a general framework for deriving
> extra keys, we can do something like:

Gah, typo again:

> EK = 3rd output from Split().HKDF()
> CK_PSK, PSK_0 = HKDF(EK, "PSK")
> CK_PSK, PSK_1 = HKDF(CK_PSK, "")
CK_PSK, PSK_2 = HKDF(CK_PSK, "")

Trevor