Re: dissemination of public encryption certificates

["Alberto Cozer" <[e-mail]>]

Julien,

I have seen this idea in the past, but so far no RFC nor any agency 
officialy documented it. We should have an hierarchical structure for 
public directories, similar to the DNS hierarchy. Maybe the DNS hierarchy 
itself could be used for that. We could have a new DNS record type (DRY, 
from Directory, for instance). Then, as mail servers and clients consult 
MX record to deliver a message they could check for the DRY record to 
deliver S/MIME messages. Without this DRY record set in the DNS zone file, 
must be possible to deliver a signed message but impossible to deliver an 
encrypted one. 

In my oppinion it is really hard to solve the public keys problem without 
changing the way people send e-mails. With minor changes in the DNS and 
E-MAIL RFC's would be possible to have people sending and receiving 
encrypted mail transparently in a couple of years. 

Best regards,

Alberto Cozer
Security Outsource Director, Future Technologies Digital Security
IBM Certified AIX System Specialist
Checkpoint Certified Security Expert, CCSE NG
[e-mail]
http://www.fti.com.br
Tel / Fax: [phone]






[e-mail] (Julien Pierre)
Sent by: [e-mail]
08/08/2003 23:07
 
        To:     [e-mail]
        cc: 
        Subject:        dissemination of public encryption certificates


Hi,

Since this is my first posting to this mailing list, let me introduce 
myself :

I'm a software engineer in AOL / Netscape and one of my responsibilities 
for several years has been to maintain the open source Netscape Security 
Services (NSS) library, which is used in the Mozilla browsers, many 
Netscape and Sun servers, and other internal products. The NSS library 
contains an implementation of S/MIME v3.

I was wondering what thoughts you may have on the following problem :

If I have a keypair and e-mail certificate, and I want to send encrypted 
e-mail to somebody knowing his e-mail address, what's a systematic way 
to obtain the recipient's encryption certificate ?

Traditionally today, signed e-mail messages typically contain the 
signer's public encryption certificate. However that means one party 
needs to first send a signed unencrypted, e-mail message to transmit the 
public encryption certificate before both parties can exchange encrypted 
messages.

There are also ways to find recipient certificates today using corporate 
directory servers, but users must know about them and manually configure 
them in their applications, and they are typically not widely available 
on the Internet.

I'm envisioning some standardized scheme where, by starting with the 
recipient's email address, it would be possible to locate a public 
directory server, then find the recipient's certificate by looking it up 
in that directory server.

My main question is : has any similar scheme been proposed ? I would 
rather work with something that exists, but if there is nothing that 
fits, I'm open to writing an RFC.

Also, what are the other ways that people locate recipient S/MIME e-mail 
encryption certificates ?

Thanks.