This draft pertains to issues of confidentiality and integrity of end-to-end email messages. I have a working knowledge of these protocols, but not an expert so this will only pertain to the sections that mention the DNS in some way.

The only mention of DNS or DNS RRsets is in the "Future Work" section with a discussion on certificate discovery using the DNS to store and retrieve SMIMEA or OPENPGPKEY RRsets.  No discussion is presented in this version and instead listed as something to be discussed in future versions. So this version of the draft has no DNS implications, but future updates might need additional review if these sections are added.

Scott