[6tisch] Terminology for minimal security

[Mohit Sethi <[e-mail]>]

Hi Malisa

I am now reviewing the minimal security as well as the OSCoAP and EDHOC 
documents. While it will still take some time for me send out a detailed 
review,  I have some comments on the confusing terminology used in your 
presentation.

First, the slides where you explain key generation at pledge. What is 
the "Key" on the slide? How is this "Key" different from the PSK? The 
slide says key generation but use a HKDF. Which one is it? Key 
generation or derivation? Do you use them interchangeably?

Also for the Nonce generation slides and in the draft, please say 
explicitly "AEAD Nonce" so that it is not confused with the nonces used 
in TLS and EDHOC handshakes. Those nonces need to be fresh random bytes 
while the AEAD nonce only needs to be unique for each invocation of AEAD.

These terms maybe well understood and trivial for those working on the 
drafts, for others these can be confusing.

I have a separate question on uniqueness of AEAD nonce that I would send 
out on the CoRE mailing list.

--Mohit