Subject: Request: Send me signed messages

From: "Peter Hesse" <[email-masked]>
Date: Fri, 16 Jul 2004 12:16:02 -0400

All,

We are looking to get a cache of many "real-world" certificates with which
to do some testing related to certificate path building and validation.
Since most email clients send the signer's path (or some portion thereof)
with signed messages, I'd love to receive signed messages from anyone that
is willing to send one.  I expect the S/MIME and PKIX lists have a high
quantity of individuals with the capability to send S/MIME signed messages.

You have my personal guarantee that your email addresses will not be used or
stored by us; I have no desire to alienate the community!

You can reply to this message (NOT THE LIST) and sign your reply, or send
directly to [email-masked].

I would be willing to share the resultant set of certificates with
researchers interested in similar work.  Please contact me on my normal
address, pmhesse[at]geminisecurity[dot]com if you are interested.

Thanks,

--Peter Hesse

---

From: Ed Gerck <[email-masked]>
Date: Fri, 16 Jul 2004 11:53:12 -0700

> quantity of individuals with the capability to send S/MIME signed messages.

Comments below.

> stored by us; I have no desire to alienate the community!

This is your promise #1.

> researchers interested in similar work. 

This your promise #2. Do you think there is any conflict with your
promise #1?  What do you think we know the "resultant set of certificates"
contain?

COMMENTS: Your message is off-topic and a spam. It's free to subscribe and
listen to the traffic if you wish. Please don't burden this list.

---

From: "Peter Hesse" <[email-masked]>
Date: Fri, 16 Jul 2004 15:22:12 -0400

Ed,

I do not see why you felt it necessary to send this spiteful message.  I
have been an active participant in PKIX for 7 years now (S/MIME somewhat
less time), and I'm the editor and co-author of the current PKIX document on
certification path building.  I am not subscribed to the list to spam or to
burden the list.  As I said in my earlier message, I thought that these
lists contained the largest groups of individuals capable of sending signed
email messages.

Obviously before I share the collected certificates with any other
researchers, I will require a similar promise for those researchers to keep
the email addresses therein confidential.  

If anyone is afraid of what I might do with the collected email messages or
certificates, just don't send me a message.  I won't be offended.  I am
confident that those that know me, know of me, or know of my company have no
such fears; many have already sent me messages.  For that I thank you, and I
expect that the resultant set of data will be useful in the creation and
improvement of certification path development and validation software in the
years to come.

--Peter

+---------------------------------------------------------------+
| Peter Hesse                    [email-masked]     |
| Phone: (703)934-2031         Gemini Security Solutions, Inc.  |
| ICQ: 1942828                     www.geminisecurity.com       |
+---------------------------------------------------------------+
"Pay no attention to what the critics say; there has never been 
a statue set up in honor of a critic." --Jean Sibelius

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Ed Gerck
> Sent: Friday, July 16, 2004 2:53 PM
> To: Peter Hesse
> Cc: [email-masked]; [email-masked]
> Subject: Re: Request: Send me signed messages
> 
> 
> 
> 
> Peter Hesse wrote:
> 
> > All,
> > 
> > We are looking to get a cache of many "real-world" 
> certificates with 
> > which to do some testing related to certificate path 
> building and validation.
> > with signed messages, I'd love to receive signed messages 
> from anyone 
> > that is willing to send one.  I expect the S/MIME and PKIX 
> lists have 
> > a high quantity of individuals with the capability to send 
> S/MIME signed messages.
> 
> Comments below.
> 
> > You have my personal guarantee that your email addresses 
> will not be 
> > used or stored by us; I have no desire to alienate the community!
> 
> This is your promise #1.
> 
> > You can reply to this message (NOT THE LIST) and sign your 
> reply, or 
> > send directly to [email-masked].
> > 
> This your promise #2. Do you think there is any conflict with 
> your promise #1?  What do you think we know the "resultant 
> set of certificates"
> contain?
> 
> COMMENTS: Your message is off-topic and a spam. It's free to 
> subscribe and listen to the traffic if you wish. Please don't 
> burden this list.
>

---

From: Ed Gerck <[email-masked]>
Date: Fri, 16 Jul 2004 12:43:14 -0700

> the email addresses therein confidential.  

Peter,

An obvious problem with email certificates is that they open us to spam.
You promised you will not share (emails) what you promised to share (certs
with emails).  I am glad you agree your two promises were not consistent.

Also, please take a look at your message in the PKIX archive:
http://www.imc.org/ietf-pkix/mail-archive/msg02908.html
You will notice that PKIX protects your email address.

Of course, I am familiar with your name in this list. One more
reason for you to be thankful that I used my time to point out
what you missed. It can happen to any one of us.

Cheers,
Ed Gerck

---

From: Stephen Kent <[email-masked]>
Date: Fri, 16 Jul 2004 17:03:11 -0400

I view Peter's solicitation for signed e-mail to be appropriate for 
the PKIX WG list.

Steve

---

From: Joseph Doekbrijder <[email-masked]>
Date: Mon, 19 Jul 2004 11:20:07 +0200

Interesting issue, which leaves me with a question:
The only thing a spammer can not do (or maybe only once) is digitally 
sign his spam! Upon abuse, The cert can be put on the receivers 
"black-list", the cert could be revoked by CA and/or RA and the 
IssuingParty can be contacted if abuse continues...
Would it thus not be an interesting approach to build a mail filter that 
filters out all non digitally signed email?
It is clear, this is something for the future, but from a theoretical 
point-of-view: Some feedback from the experts out there would be 
interesting for me. In other words, can we take this any further?

Cheers

Josh

-- 
Joseph A. Doekbrijder
--------------------------------------------------
SwissSign AG
Löwenstrasse 1, CH-8001 Zürich
Tel: +41 43 344 88 11 / Mobile: +41 79 211 24 46
www.swisssign.com
--------------------------------------------------

This message has been digitally signed to ensure unaltered and 
authenticated reception. Should you receive an error message regarding 
the validity of the signature, please click and download the SwissSign 
root certificate using the following link  https://swisssign.net/trust/
After installation, your mail client will be able to automatically 
verify the authenticity of e-mail messages sent to you by users of 
SwissSign certificates.

---

From: Christine Karman <[email-masked]>
Date: Mon, 19 Jul 2004 12:51:33 +0200

>An obvious problem with email certificates is that they open us to spam.

How's that?
If you accept encrypted email, then you can refuse unsigned email. Besides, 
most of our customers use gateway decryption, which allows them to do 
content scanning.

dagdag
Christine

--
Izecom BV
Secure e-mail and digital signatures
www.izecom.com

if your outlook can't reply to a signed message, go to 
www.izecom.com/reply.html

---

From: Christine Karman <[email-masked]>
Date: Mon, 19 Jul 2004 15:19:57 +0200

At 03:13 PM 7/19/2004, you wrote:

>Um, the cert tends to have your (valid) email address in it.

Peter already has my email address through this list, so why shouldn't I 
send him my certificates?

dagdag
Christine

---

From: "Timothy J. Miller" <[email-masked]>
Date: Mon, 19 Jul 2004 08:13:28 -0500

Christine Karman wrote:

> How's that?
> If you accept encrypted email, then you can refuse unsigned email. 
> Besides, most of our customers use gateway decryption, which allows them 
> to do content scanning.

Um, the cert tends to have your (valid) email address in it.  (And 
support for certs without an rfc822Name is spotty at best.)

-- Tim

---

From: Ed Gerck <[email-masked]>
Date: Mon, 19 Jul 2004 17:26:02 -0700

>> An obvious problem with email certificates is that they open us to spam.

A repository of certs with email addresses is a repository of email addresses.

> If you accept encrypted email, then you can refuse unsigned email. 

You can do the latter without doing the former. Beseides, while it's relatively easy
to send signed email to many people (as it depends only on your cert), in order
to send encrypted email to many people you need each recipient's cert (and you also
want to make sure they are not revoked at the time they receive the message, which
is yet another problem).

Cheers,
Ed  Gerck

---

From: Joseph Doekbrijder <[email-masked]>
Date: Tue, 20 Jul 2004 11:48:58 +0200

> want to make sure they are not revoked at the time they receive the 

Why does the sender need to make sure that the encryption certificate of 
the receiver is not revoked at the time the message is received?
IMHO this is irrelevant. (Otherwise one would not be able to read very 
old messages, etc...)

---

From: "Al Arsenault" <[email-masked]>
Date: Tue, 20 Jul 2004 07:22:31 -0400

Actually, the sender can't control anything about the time the recipient
receives the message. All he can do is verify that the recipient's
certificate is not revoked at the time the message is sent, as the sender
perceives the time.

	Al Arsenault

> From: [email-masked]
> [mailto:[email-masked]]On Behalf Of Ed Gerck
> Sent: Monday, July 19, 2004 8:26 PM
> To: Christine Karman

---

From: Ed Gerck <[email-masked]>
Date: Tue, 20 Jul 2004 09:32:24 -0700

> certificate is not revoked at the time the message is sent, as the sender

Agreed. That's why what would really be desirable [1] cannot be done and
it's an additional problem when sending encrypted email. The same does not
happen with signed email, because the message is usually considered valid if
the cert was valid at the time the message was signed.

Cheers,
Ed Gerck

[1] Ed Gerck wrote:
>> in order to send encrypted email to many people you need each recipient's
>>cert (and you also want to make sure they are not revoked at the time they 
 >> receive the message, which is yet another problem).

---

From: Ed Gerck <[email-masked]>
Date: Tue, 20 Jul 2004 09:43:08 -0700

> IMHO this is irrelevant. (Otherwise one would not be able to read very 

Suppose you encrypt a message to Bob at time T, using Bob's PK cert that
is not revoked at time T (as you verify the CRL). Due to email delays, the
message is delivered at time T + D, at which time Bob's PK cert has been
revoked due to key compromise reported by Bob after time T but before T + D.
The end result is that, unwillingly, you sent Bob an insecure message because
you used his compromised key.

This risk, while not fully preventable, can be reduced. For example, suppose
you estimate that the email delay will not be larger than 5 minutes. You verify
a CRL for Bob's cert and, if the CRL was issued more than 5 minutes ago, wait
for the next CRL and send the email within 5 minutes of its publication. This
can be easily automated by you, using the freshestCRL field.

Cheers,
Ed Gerck

---

From: Massimiliano Pala <[email-masked]>
Date: Fri, 23 Jul 2004 10:38:45 +0200

> interesting for me. In other words, can we take this any further?

Actually we do believe this could be an interesting approach to investigate.
At present we are working on an Email Policy Enforcer (EMPE) that seems
to be promising and uses strong authentication methods to solve some of
the email-related issues. I guess we'll be able to publish something about it in
the near future.

If it is not so OT I will send a pointer to it to the list.

-- 

Best Regards,

	Massimiliano Pala

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