ietf-dkim
[Top] [All Lists]

Re: [ietf-dkim] The URL to my paper describing the DKIM policy options

2006-07-27 11:07:38

On Jul 27, 2006, at 10:20 AM, Stephen Farrell wrote:



Douglas Otis wrote:
On Jul 27, 2006, at 2:09 AM, Mark Delany wrote:
So it could be an alias entry in SSP then. One is called "I sign all" and the other is called "I don't send". They both set the same bit.

There is a slight difference between these two scenarios. This difference between "All Signed" and "Don't Send" becomes significant when deciding what to do with an invalid signature.

Presumably only if the domain published some key for some selector though which I guess you'd only do if you actually do sign something (or have crazy s/w that creates keys without saying so:-).

Not finding a key represents a PERMFAIL (no key for signature). Both no key and PERMFAIL are due to several causes, where the Base draft does not indicate that there be special handling resolving even PERMFAIL.

DKIM Base:
,---
|6.1  Extract Signatures from the Message
|...
| In the following description, text reading "return status
| (explanation)" (where "status" is one of "PERMFAIL" or "TEMPFAIL")
| means that the verifier MUST immediately cease processing that
| signature.  The verifier SHOULD proceed to the next signature, if any
| is present, and completely ignore the bad signature.
'___

This statement clearly places invalid signatures into one pile, key or no key. If there is a desire to special case specific conditions leading to PERMFAIL, then policy seems a good place to make this resolution explicit.

-Doug
_______________________________________________
NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html

<Prev in Thread] Current Thread [Next in Thread>