Subject: RE: IBM alternative to PKI?

From: Trevor Perrin <[email-masked]>
Date: Thu, 16 May 2002 12:33:42 -0700

Hi Lynn (and greetings to PKIX, 1st-time poster here),

A counter-argument: while adding a middleman adds a vulnerability, it also
adds auditing: the middleman can monitor all password attempts, so as to:
 - lockout guessers
 - detect anomalous patterns of use which may indicate a compromised
password is being exploited
 - allow users to review audit trails to detect compromises themselves
 - allow users to review audit trails to determine the extent of a
compromise

Without this auditing, it may be much more difficult to detect a compromise
of a private key, and to determine precisely what has been compromised.

So there are security benefits as well as disadvantages to middlemen, I
suppose a comparison depends on the exact situation and how you weight the
factors..

Trevor

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Thursday, May 16, 2002 10:00 AM
To: Anders Rundgren
Cc: Dean Adams; [email-masked];
[email-masked]
Subject: Re: IBM alternative to PKI?

i.e. middle-man tends to represent transition/roll-out solutions .... not
security infrastructure solutions.

from traditional security

* end-to-end

middle-man approaches tend to always negate any end-to-end attribute

* additional steps represent additional vulnerabilities

middle-man approaches increase the number of steps/processes .... each of
which represent an additional vulnerability, each additional vulnerability
represents additional points of failure/fraud

* only as strong as the weakest link

shared-secret password paradigm in series with digital signature isn't
additive.

* 2-factor authentication

secret password (as opposed to shared-secret password) in conjunction with
hardware token (i.e. processing in parallel instead of in series)
represents a combination link (both hardware token and secret password has
to be compromised). a shared-secret password process in series with a
digital signature process can fail with just the shared-secret password.

---

From: Ricardo Barroso <[email-masked]>
Date: Fri, 17 May 2002 17:23:25 +0100

>adds auditing: the middleman can monitor all password attempts, so as to:

That's an advantage but that will also probably be a serious source of
DOS attacks!

 >suppose a comparison depends on the exact situation and how you weight the

Regards,
Ricardo Barroso