While it is true that the inclusion of attribute certificates will cause
this problem, that is going to be a rare item in the current world. This is
going to generally be in closed (or semi-closed) rollouts and not hit the
internet in general.
Existing clients will be able to read messages which include secure receipt
requests, they would not generate a return receipt. There may also be some
issues about current clients reading an acutal receipt, but that is the
unexpected not expected case.
jim
-----Original Message-----
From: Blake Ramsdell [mailto:BlakeR(_at_)deming(_dot_)com]
Sent: Monday, November 23, 1998 2:56 PM
To: Jim Schaad (Exchange); 'Russ Housley';
pgut001(_at_)cs(_dot_)aucKland(_dot_)ac(_dot_)nz
Cc: ietf-smime(_at_)imc(_dot_)org
Subject: RE: RecipientInfo vs SignerInfo key identification
-----Original Message-----
From: Jim Schaad (Exchange)
[mailto:jimsch(_at_)EXCHANGE(_dot_)MICROSOFT(_dot_)com]
Sent: Monday, November 23, 1998 2:47 PM
To: Blake Ramsdell; 'Russ Housley';
pgut001(_at_)cs(_dot_)aucKland(_dot_)ac(_dot_)nz
Cc: ietf-smime(_at_)imc(_dot_)org
Subject: RE: RecipientInfo vs SignerInfo key identification
These discussions occured when we were still meeting in San
Fransico. If we
allow for this to occur in the S/MIME world we immeadiately
hit the demon of
backwards compatability. I don't know about your product,
but ours does not
look at capabilites of recipients when sending signed mail.
Thus we MUST
use the Issuer/Serial Number identification as we have no idea if the
receiving client has the ability to understand anything new.
Isn't this a problem if you have attribute certificates or secure return
receipts also? These features will not be supported by v2 clients either
(and will cause a similar interoperability problem).
Likewise, the RecipientInfo changes for this same purpose seem to have
exactly the same problem (and we got around this by ticking the version
number), so the demon is still with us.
I personally don't want this changed, but I wanted to make sure I understood
the arguments against it.
Blake
--
Blake C. Ramsdell
Worldtalk Corporation
For current info, check http://www.deming.com/users/blaker
Voice +1 425 882 8861 x103 Fax +1 425 882 8060