Re: [Endymail] Improvements to S/MIME

[Phillip Hallam-Baker <[e-mail]>]

On Sun, Sep 14, 2014 at 4:13 AM, Wei Chuang <[e-mail]> wrote:
>
>
> On Sat, Sep 13, 2014 at 10:54 AM, Werner Koch <[e-mail]> wrote:
>>
>> On Fri, 12 Sep 2014 19:48, [e-mail] said:
>>
>> > 1) S/MIME doesn't fully protect users mail envelope metadata.  For
>> > example
>> > the recipient and envelope-sender must be visible to the intermediate
>> > SMTP
>>
>> If you want that, it is easy to put the messaqge into a message/rfc822
>> mail container and use faked subject and other mailer header.
>
>
> Right I agree that there is a RFC5751 sec 3.1
> (http://tools.ietf.org/html/rfc5751#page-18 ) that mentions the
> message/rfc822, but unless I'm missing something one still has to specify
> the intended recipient, and a return path.  Even if the body and most
> headers were wrapped hence private, an adversary could still find the
> sender/recipient information very useful.

I suggest that we stick to exchanging endymail with disclosure of the
routing information before we go on to the traffic analysis prevention
problem.

It is possible to prevent traffic analysis but that is a transport
issue pretty much by definition. So it would suggest we look at S/MIME
+ TLS rather than one alone. And if they don't serve then we look at
Tor and Mixmaster...