Re: [Endymail] Improvements to S/MIME

[Wei Chuang <[e-mail]>]

On Sat, Sep 13, 2014 at 11:46 AM, Phillip Hallam-Baker <
[e-mail]> wrote:

> On Sat, Sep 13, 2014 at 1:54 PM, 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.
>
> Again there is a difference between what you can do and a standard.
>
> I think that 80% of what we need to do could be done in a profile of
> S/MIME that says stuff like
>
> * MUST support AES-128, AES-256
> * MUST support [choose order of encrypt + sign]
> * MUST support domain level certs for end entity
> * MUST support message/rfc822 encrypted payload
>
> What we need to add on top is really not so difficult:
>
> * Mechanism for discovering recipient encryption preference, format
> support (PGP/SMIME), algorithm support and encryption key
>

Two ideas:
1) DNS (either new TXT entry or new record type)
2) EHLO SMTP extension


> * Mechanism for direct trust, aka key fingerprint
> * Mechanism for private key maintenance
>

Is this issue key rotation?

-Wei