New RFC for Publishing DKIM Signature Policy

A new RFC allows to publish the policy for using DKIM signatures on outgoing emails. There are two ways to use DKIM:

• use a valid DKIM header as an indication that the email is legit
• use a missing DKIM header as an indication that the email is spam.

However, the first option fails if the spammer registers a domain and adds a valid DKIM header. The second option cannot be used if the domain in question simply doesn't use DKIM. Now there is a new option:

• use a missing DKIM header as an indication that the email is spam and the sending domain announces that they use DKIM

This sounds reasonable to me.