[noise] Test vector format

[Alex]

On Fri, 8 Apr 2016 19:25:06 -0700
Trevor Perrin <trevp at trevp.net> wrote:

>  - What are the semantics for "name", does it have to be unique?

If a handshake fails it would be nice to be able to identify it in
debugging messages. So, while uniqueness isn't required, it certainly
would be helpful.

>  - "fail" will usually be "false", so it's mostly redundant and just
> takes up space.  I didn't mind "payload": null or some other special
> value to indicate failure.  Alternatively the "payload" line could be
> replaced by the "fail": true line, for error cases?
> 

My approach for verifying the vectors is to replay both sides of the
conversation while collecting the (payload, ciphertext) pairs at each
step. After the entire conversation is over -- i.e. all payloads in the
"messages" array have been converted to ciphertext -- the "messages"
array from the file and the results from the replayed conversation are
tested for equality. Due to this, I am not keen on a "payload: null"
line to indicate failure, because the message sender needs a payload to
generate a ciphertext (encryption never fails, only decryption does).
This also applies to omitting the "payload" key entirely.

How about defining the "fail" value as False by default if it's
omitted or null, and only including it if it's True?

-- 
Alex