[noise] Versioning (was Re: Noise Certificates?)

[Stephen Touset]

On Jul 30, 2014, at 8:26 PM, Trevor Perrin <trevp at trevp.net> wrote:

> Alright, proposal for minimal versioning:
> - precede all messages with 1-byte version
> - defaults to zero, and to reject non-zero values
> - libraries should provide callbacks to set or examine version values
> 
> The idea is you can ignore the version until you need it, and then you
> have a handy way to signal upgrades or whatever.
> 
> We'd talked about presenting specific structures for the different
> types of boxes.  So combining all this would be:
> 
> struct {
>    bytes encrypted_sender_pubkey[DH_LEN];
>    bytes mac[MAC_LEN];
>    NoiseBody body;
> } NoiseBox;
> 
> struct {
>  byte version;
>  bytes ephemeral_pubkey[DH_LEN];
>  NoiseBox box;
> } StandaloneBox;
> 
> struct {
>  byte version;
>  bytes ephemeral_pubkey[DH_LEN];
>  NoiseBox box;
> } ServerBox;
> 
> struct {
>  byte version;
>  NoiseBox box;
> } ClientBox;
> 
> struct {
>  byte version;
>  bytes ephemeral_pubkey[DH_LEN];
> } ClientStart;
> 
> 
> The pipe handshake would be:
> C->S:  ClientStart
> C<-S:  ServerBox
> C->S:  ClientBox
> 
> Thoughts?

Much clearer.

-- 
Stephen Touset
stephen at squareup.com