Review of updates Section 5.1.3.4 and Appendix E

[HBrock]

I updates the section on mesage protection using a KEM key pair and added an appendisx on different szenarios regarding which side owns the KEM key.

Any review is appreciated.

[HBrock]

Meeting 11.05.23 Improve the first paragraphe regadring terminoligy 'sender' and 'recipient'. May be add som text like Mike proposed: "Here we use the term "sender" to mean the entity initiating a given request, who needs to be authenticated, and "recipient" to mean the entity who needs to authenticate the request being received. In case the sender ..."

[HBrock]

Mike proposed adding a note explaining why Bob used the KDF not together with the KEM.

[HBrock]

It was aslo discussed to extend the description of steps 1-3 of figure 2 more explicitly, like in older versions of the document.

[HBrock]

done