[ietf-dkim] RFC4871bis - whether to drop -- l= and x=

[Doug Otis]

On Jun 2, 2009, at 2:10 PM, Paul Russell wrote:

> Ah! I have a less-than-complete understanding of the current  
> specification. Why does the current specification allow the signer  
> to specify an arbitrary value for l=, rather than requiring the  
> value of l= to be the actual length of the message body at the time  
> the message is signed?

There are cases where a receiving MTA or delivery agent will append a  
notification to incoming messages.  For example, when the DKIM  
signature is checked after being forwarded and the i= parameter has  
been used, appended notifications will not affect the signature  
verification process.  Appended portions of a message will need to be  
annotated differently, in the same manner unsigned headers should also  
be annotated differently.  Proper annotation may require greater  
annotation flexibility, or perhaps creation of message copies  
containing only signed information.  How messages are annotated is  
beyond the scope of the DKIM specifications.

-Doug