ietf-smime
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RE: dissemination of public encryption certificates

2003-08-14 15:46:57
Philip,

Hallam-Baker, Phillip wrote on 08/14/2003, 10:30:

1) Signature
        Signature is only possible by changingthe message format.
Unfortunately there are still a lot of people out there with broken, non
S/MIME capable email clients. Probably more of those than have broken
email
servers. Of course at this point it is difficult to do anything about
this.

I don't think there is any way around that problem, the client simply 
must have at least basic MIME support to support S/MIME signed messages.
Unfortunately, there are many e-mail clients that cannot be supported, 
eg. the very basic e-mail "clients" included in some devices such as 
older cell phones.
The best that we can do is ensure that new client software going forward 
has the proper MIME & S/MIME support.

2) Encryption
        Encryption is a big problem for end users, it is simply not
transparent. We need to link PKI to the DNS in some way, the SRV service
looks the best choice. LDAP is not going to be the answer here, even
if you
find the right LDAP server the schema issues still have to be solved.
Sure
LDAP could address the problem - but only to the extent a Turing machine
could and only with changes to make LDAP aware of PKI concepts like trust
paths.

I think you are overly pessimistic here about the ability of LDAP to 
solve the problem. I agree with you however that a proper schema needs 
to be in place, and that is certainly a problem that hasn't been solved.

3) The end to end obsession
        One of the major reasons the IETF has failled in the security
space
is that the end to end principle alone does not address security issues.
Perimeter security is a major concern for enterprises.

        As I have been digging into this issue I have discovered that
'end-to-end security' is actually a shiboleth. Go look at the RFCs with
security architecture design discussions and you will not find it. Clark
never applied it to security either in the naive form that has become the
received version.

        What we need to do is to build specs that address multi-layer
security concerns. It should not be necessary for everyone to have a
certificate just to be able to do security. It should be possible to sign
outgoing messages at either the end user level OR the domain name
level - I
only care that an email came from Merril Lynch, not that it came from
Freddy
Bloggs in accounts.

S/MIME signing can be implemented transparently in the way you want as 
well. Merryl Lynch could have a certificate with regular expressions in 
it, matching all of its employees. The internal Merryl SMTP e-mail 
server, perhaps setup with SSL and some basic authentication of 
employees, could automatically sign each outgoing e-mail message with 
that certificate. This really is not end-to-end at all but I believe it 
can work today. You just have to be a little creative.

The solution is (and always has been) to do a lookup.  The
problem is that
there is no directory to look up from.   Global X.500/LDAP
directories are
*never* going to happen.

Amen brother, Amen.

I find it really ironic that I can lookup phone numbers for anyone 
listed in the united states, knowing such sensitive information as their 
name and physical address, through a free service like 
www.switchboard.com, but I can't look-up their e-mail certificate 
knowing their e-mail address ?
I'm sure there is lots of politics involved, but surely the logistics of 
running this service shouldn't be so much of a problem ?

-- 
I am the dog in dogfood



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