[noise] Lightning protocol Noise variation

[Alex]

On Wed, 29 Jan 2020 03:04:44 -0800
Trevor Perrin <trevp at trevp.net> wrote:

> On Thu, Jan 9, 2020 at 12:03 PM Janus Troelsen <ysangkok at gmail.com>
> wrote:
> >
> > Alex suggested I bring up the variation of key rotation on this
> > list, to probe the community. As I have linked in the PR, and if I
> > understand correctly, one lightning-rfc spec writer claims that
> > Lightning uses the key rotation it does (with two chaining keys)
> > because it was developed before key rotation was added to Noise.  
> 
> I think that's right (the Lightning mechanism pre-dates the Noise
> rekey mechanism).
> 
> Glancing at it again, it looks fine (because HKDF is a PRF it can be
> understood as just applying a chain of PRFs to the secure key CK).
> 

Thank you Trevor!

Janus: I'll re-visit the issue in the next few weeks.

Alex