[ietf-dkim] Nits with section 1 Introduction

[Arvel Hathcock]

Some minor suggestions:

1.  Introduction

    Second and third paragraph potential rewrite:

    "However, the legacy of the Internet is such that not all messages 
will be signed.  Therefore, the absence of a signature is not an a 
priori indication of forgery.  In fact, during early phases of DKIM 
deployment it must be expected that most messages will remain unsigned.  
Nevertheless, some domains may find it highly desirable to advertise 
that they sign all their mail making the absence of a valid signature a 
potential indication of forgery.  Without a mechanism to do so the 
benefits of DKIM are limited to cases in which a valid signature exists 
and can not be extended to cases in which signatures are missing or are 
invalid.  Defining such a mechanism is the purpose of Sender Signing 
Practices."

  "In the absence of a valid DKIM signature on behalf of the "From" 
address [RFC2822], message verifiers implementing this specification 
MUST determine whether messages from that address are expected to be 
signed and what signatures are acceptable.  This determination is 
referred to as a Sender Signing Practices check."


    Fourth paragraph, start of first sentence:  "Conceivably, Sender 
Signing Practices could be extended in the future..."

(more coming)

Arvel