[ietf-dkim] Proposal for specifying syntax and semantics for multiple signatures

[Stephen Farrell]

Doug,

Douglas Otis wrote:
> 
> On Apr 4, 2006, at 8:44 AM, Dave Crocker wrote:
>> Douglas Otis wrote:
>>>> Sorry, I still don't understand what the purpose or impact of this 
>>>> attack is. Can you explain?
>>>
>>> An attack may be enabled by replaying a message compromised due to a 
>>> weak hash, key, or canonicalization algorithm.
>>
>>
>> You didn't answer his question (or, by derivation, mine.)
> 
> DKIM can establish a trust relationship between the signing-domain and 
> the recipient.  Being able to exploit that trust relationship can be 
> used to both defraud the recipient, and damage the trust that might have 
> been established by the signing-domain.  If there is an exploit that 
> becomes a problem, both parties should be able to quickly upgrade and 
> find protection.
> 
> The message may have been a message a financial institution asking to 
> check the account and offering a helpful login link.  The recipient 
> might trust this link when lead to understand this domain signs their 
> messages and that their MDA/MUA places non-compliant messages into their 
> spam folder.

Nor can I see what this has to do with removing one of a bunch of
signatures.

Maybe we should move on and you can raise the replay issue again
later (I bet you will, eh:-)

S.