Re: The subject line leakage problem

[Paul Hoffman / IMC <phoffman@xxxxxxx>]

This is getting much more complicated than it needs to be, and is 
likely to break interoperability with non-enhanced clients.

The simplest thing to do is to say:
- Senders should put the minimum that they want in the unprotected headers
- Senders include as much as they want protected in a 
text/rfc822-header part at the beginning of a multipart/mixed message
- Enhanced clients should display the message with the headers from 
the text/rfc822-header part moved to where the user thinks he/she 
sees the headers. In the case of headers that are in both in the 822 
message and in the text/rfc822-header body part, the latter wins 
(because it is protected)
- The moved-up headers may cause side-effects that the MUA should act 
on. For example, if the Cc: in the 822 headers is "bill@xxxxxxxxxxx" 
but the Cc: in the protected headers is "amy@xxxxxxxxxxx", the "reply 
to all" action should include amy but not include bill.

--Paul Hoffman, Director
--Internet Mail Consortium