Re: Why are mail servers not also key servers?

[Doug Royer <[e-mail]>]

On 04/21/2017 06:06 AM, Philip Homburg wrote:
>> You send me a signed email from a mutually trusted source. I now have
>> your public key, because you can extract it from the signed S/MIME
>> email. (I am guessing you can do this with PGP.)
> 
> Just replying to a random part of the discussion.
> 
> Is there any kind of description and any kind of agreement of what attacks
> secure mail is supposed to defend against?

I am not a security expert, I did however buy a couple of them lunch at 
an IETF meeting years ago and I am sure that the experts will correct 
any misstatements I have made here. S/MIME has been working for years.

> Without a clear statement of what it is supposed to do, it is not possible
> to figure out whether a proposal actually meets that goal. And without a
> clear goal it is also not possible to figure out if the system is going to
> useful or not.

To be clear, this is not a goal or proposal. This is how S/MIME works 
now. This is how it was designed to work.

> People have wildly different ideas of what e-mail security means.
> 
> In the context of this discussion, one thing I'm curious about, and something
> that should be clear from the description of the attack vectors, is who
> controls a key.

You should be in control of your private keys. You private key is as 
secure as you make it. The average non-technical user will just send 
email, get email, and might make sure that the signed, or encrypted 
email checkbox is checked in their MUA.

> To put it in terms of TLS certificates, is an e-mail key 'DV' or 'EV'?

> It is easy to come up with lots of ways in which a domain holder can provide
> a public key for a mailbox at that domain. But is that what we want?
> In some cases, like corporate mailboxes, probably yes. In other cases,
> journalists or activists with an e-mail account at a big e-mail provider,
> probably not.

The only reason you need to fetch a persons private key first, is so 
that you do not have to exchange the signed and not encrypted key first.

And I would imagine that a journalist and activists would most 
definitely want people to send them encrypted email.

-- 

Doug Royer - (http://DougRoyer.US  http://goo.gl/yrxJTu )
[e-mail]
714-989-6135