Subject: PGP 6.5.1 - word list and SDAs?

From: Thomas Roessler <[email-masked]>
Date: Wed, 7 Jul 1999 11:14:35 +0200

It would have been nice to have had some specifications on _this_
list _beforehand_:

- What do the SDAs look like?  Not everyone is using the same
  platform, so documentation of the data format would have been nice.

- What's the word list mapping for fingerprints?  I think this
  should be published at least as an informational RFC, so
  third-party products can produce compatible "fingerprint
  sentences".

Thanks, tlr  

----- Forwarded message from Cody Brownstein <[email-masked]> -----

Date:         Tue, 6 Jul 1999 18:21:39 -0700
From: Cody Brownstein <[email-masked]>
Subject:      PGP 6.5.1 has been released
To: [email-masked]

<http://web.mit.edu/network/pgp.html>

NEW FEATURES IN 6.5.1

PGPnet. PGPnet is a landmark product in the history of PGP. PGPnet secures
all TCP/IP communications between itself and any other machine running
PGPnet. PGPnet has been successfully tested with Cisco routers(requires
Cisco IOS 12.0(4) or later with IPSec TripleDES), Linux FreeS/WAN, and many
others.

Self-Decrypting Archives. You may now encrypt files or folders into
Self-Decrypting Archives (SDA) which can be used by users who do not even
have PGP. The archives are completely independent of any application,
compressed and protected by PGP's strong cryptography.

Integrated PGP Command Line. This version incorporates the popular command
line version of PGP for Windows platforms. This product provides you a
convenient way to integrate PGP with other Windows applications and
automated processes on your desktop system. Please note that this is
intended for single user/workstation use. For use on servers, customers are
required to purchase the PGP Command Line/Batch Server product. Please
contact your local Network Associates Sales representative for more
information.

Automated Freespace Wiping. PGP's Freespace Wipe feature now allows you to
use the Windows Task Scheduler to schedule periodic secure wiping of the
freespace on your disk.

Hotkeys. The Use Current Window feature has been significantly enhanced by
the addition of Hotkeys. By pressing the configured key combination, the
Encrypt/Decrypt/Sign functions can be automatically invoked in zero clicks
without using PGPtray.

Fingerprint Word List. When verifying a PGP public key fingerprint, you can
now choose to view the fingerprint as a word list instead of hexadecimal
characters. The word list in the fingerprint text box is made up of special
authentication words that PGP uses and are carefully selected to be
phonetically distinct and easy to understand without phonetic ambiguity.

Support for Outlook 2000 and Outlook Express 5.0. This version of PGP adds
support for sending and receiving encrypted e-mail in Microsoft Outlook 2000
and Outlook Express 5.0.

HTTP Proxy Support. If you are behind a corporate firewall with an HTTP
proxy server, PGP now supports accessing HTTP keyservers through the proxy.
To use this feature, you must configure the proxy server address in your
Internet Explorer preferences.

Smart Word Wrapping. The word wrapping in PGP now automatically rewraps
paragraphs and even quoted paragraphs resulting in much cleaner signed
messages.

-----
Cody Brownstein
<[email-masked]>
-----

PGP Fingerprint:
291B 5051 B97F 8B30 49F8  A068 15CF 26D6 E4DE 5291

----- End forwarded message -----

---

From: Will Price <[email-masked]>
Date: Wed, 07 Jul 1999 02:38:43 -0700

>   platform, so documentation of the data format would have been

Self Decrypting Archives use a proprietary format for which there is
no reason for us to publish specs beyond the source code we already
publish.  SDAs decrypt themselves.  No other program should attempt
to read them, and we will change the format at will frequently.  Each
implementation of SDA in PGP uses highly platform dependent features.
 There are not two ends of this wire.  SDAs are irrelevant to this
list, and have no relation to the OpenPGP format.

>   third-party products can produce compatible "fingerprint

High level biometric authentication methods that a particular vendor
(in this case Network Associates) chooses to implement are well
beyond the scope of this list.  These issues have no effect
whatsoever on the data format used by OpenPGP.  Technical
documentation and mappings for the word lists are published in the
docs for PGP where they belong.  Not in this group.

- -- Will

Will Price, Architect/Sr. Mgr., PGP Client Products
Total Network Security Division
Network Associates, Inc.

---

From: Werner Koch <[email-masked]>
Date: Wed, 7 Jul 1999 12:08:05 +0200

>   platform, so documentation of the data format would have been nice.

and how is this related to ITAR?  Sending a SDA from the U.S. to
Europe seems to be like exporting strong crypto.

just wondering..

-- 
Werner Koch at guug.de           www.gnupg.org           keyid 621CC013

---

From: Thomas Roessler <[email-masked]>
Date: Wed, 7 Jul 1999 12:20:08 +0200

On 1999-07-07 02:38:43 -0700, Will Price wrote:

> High level biometric authentication methods that a particular
> vendor (in this case Network Associates) chooses to implement are
> well beyond the scope of this list.

From the context, it should have been obvious to you that by
"fingerprint" I meant "key fingerprint", and not any biometric
authentication methods your company may or may not choose to
implement.

> Technical documentation and mappings for the word lists are
> published in the docs for PGP where they belong.  Not in this
> group.

Sorry, Will, this word mapping _is_ an interchange format for
OpenPGP key properties, so it _does_ belong on this list and into an
(at least informational) Internet RFC. After all, there is a reason
behind having a well-defined key fingerprint displayed to and
exchanged by users, isn't it?

Concerning the SDAs, having a platform-independent marker string
which indicates where the ciphertext begins shouldn't be such a
great pain, and it would enable independent implementations running
on other platforms than the one intended by the SDA's sender to
extract the ciphertext. (I'm assuming that you don't use a
proprietary format for _all_ of the SDA.)

---

From: Will Price <[email-masked]>
Date: Wed, 07 Jul 1999 04:07:05 -0700

> authentication methods your company may or may not choose to

Yes, it was obvious.  You're not seeing what I mean by biometric. 
The word list is a feature we implemented to provide better biometric
properties for key fingerprint authentication.

> OpenPGP key properties, so it _does_ belong on this list and into
> an (at least informational) Internet RFC. After all, there is a
> reason behind having a well-defined key fingerprint displayed to
> and exchanged by users, isn't it? 

I could see a case for documenting the word list we developed into an
informational RFC with no relation to this working group.  I'm sure
we'd be happy to see that happen.  However, the feature is a
biometric authentication method that has no relation to the OpenPGP
data formats.  Saying that this should have gone through OpenPGP in
the first place is like saying the PGPkeys GUI and whether RSA keys
are silver or gold should go through OpenPGP.  In theory, it's an
interesting concept to write a standard for such things so that
everybody using any implementation knows that RSA keys are silver,
but that's not the role of the IETF.  We still display display the
hex fingerprint format.  Please feel free to write an informational
RFC using the list provided in our documentation.

> proprietary format for _all_ of the SDA.)

The SDA format will change and is very fluid even now.  SDAs are not
intended to be sent from one user to another like a PGP message.  In
many cases, that would violate export controls and introduces other
concerns like viruses and trojan horses, and can't be signed.  SDAs
are a specific customer request we received many times for things
like placing conventionally encrypted items in a CD-ROM package. 
They don't use any public keys, and are not an interchange format. 
Any other OpenPGP implementation can feel free to implement their own
SDAs using their own format.  Encouraging standardization of such a
format implies that the format is a wise way to exchange encrypted
data over the wire when that is clearly not the case.  OpenPGP is the
solution for exchanging encrypted data on the wire.

- -- Will

---

From: Thomas Roessler <[email-masked]>
Date: Wed, 7 Jul 1999 13:56:05 +0200

On 1999-07-07 04:07:05 -0700, Will Price wrote:

> However, the feature is a biometric authentication method that has
> no relation to the OpenPGP data formats.  

Sorry, I don't see how an easily pronounceable and audible
representation of a key fingerprint has anything to do with what's
usually called biometric authentication.  Or are you planning to
couple PGP with voice recognition and automatic finger print
checking?

> Saying that this should have gone through OpenPGP in the first
> place is like saying the PGPkeys GUI and whether RSA keys are
> silver or gold should go through OpenPGP.

You're missing the point here.  Your user interface is exclusively
used to communicate between the software and the user.  It is _not_
used in the first place to exchange data between different users.
Unlike this, the fingerprint (and any redundant exchange format
defined for it) will be exchanged between users.

I'm looking forward for the first business card which has the
"pronouncable" finger print on its back.

---

From: Paul Koning <[email-masked]>
Date: Wed, 7 Jul 1999 09:44:40 -0400

>>>>> "Will" == Will Price <[email-masked]> writes:

 Will> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1

 >> platform, so documentation of the data format would have been

 Will> Self Decrypting Archives use a proprietary format for which
 Will> there is no reason for us to publish specs beyond the source
 Will> code we already publish.  SDAs decrypt themselves.  No other
 Will> program should attempt to read them, and we will change the
 Will> format at will frequently.  Each implementation of SDA in PGP
 Will> uses highly platform dependent features.  There are not two
 Will> ends of this wire.  SDAs are irrelevant to this list, and have
 Will> no relation to the OpenPGP format.

I assume SDAs decrypt themselves only if the recipient is using the
same CPU type and OS as the sender.  Since PGP is in other ways a
portable application, I don't think your argument holds water.  What
if someone sends me an SDA and I want to decrypt it, but I can't just
run it because he's using some random OS I don't use?  Or I'm using a
Sparc?  

	paul

---

From: Jack Repenning <[email-masked]>
Date: Wed, 07 Jul 1999 08:35:54 -0700

>defined for it) will be exchanged between users.

There are many important things in life that none the less don't belong in 
this particular document.  Does the OpenPGP Standard specify that the UI 
must present fingerprints in hex?  I don't think so; perhaps I missed 
it.  Never the less, it's vital that all implementations do so: if mine 
shows the fingerprint in decimal while yours uses hex, we're unlikely to 
manage a verification.  It's important, but it's not a part of the packet 
format.

Informix Software, Inc.        Jack Repenning
Config/Release Mgmt            [email-masked]
4100 Bohannon Drive            M/S: 4100/2
Menlo Park, CA 94025           FAX: 650/926-6571
VOICE: 650/926-1044               PAGE: 800/781-6182
PGP/RSA: D24B E2C2 9AFB 7C24 : 7E59 7885 525D 644E
PGP/DSS: 955C 44AD 8FCE 77D4 9494 \
           : 4AB2 51F1 3EED 3B82 E870

---

From: Adam Back <[email-masked]>
Date: Wed, 7 Jul 1999 21:41:05 +0100

> properties for key fingerprint authentication.

I expect the reason Will considers a word encoding of a fingerprint
has anything to do with `biometrics' is because (I'm guessing) the
word list was first designed for PGPfone where there is no web of
trust, and the only authentication is that you can recognise the
person at the other end of the phone's voice.  In that scenario you
are using your human ability to recognise the voice to authenticate a
key exchange.

You could argue that someone reading a PGP fingerprint (hex or encoded
as words) over the phone where you recognise the speakers voice counts
as a form of biometric authentication.

Adam

---

From: [email-masked] (Bodo Moeller)
Date: Thu, 8 Jul 1999 21:05:24 +0200 (CEST)

> properties for key fingerprint authentication.
[...]
>                Saying that this should have gone through OpenPGP in
> are silver or gold should go through OpenPGP.

How's that?  I don't care how the user interface that somebody else
uses looks like, but I certainly may want to verify their key
fingerprint.

>                                                 In theory, it's an
> but that's not the role of the IETF.

Coloured icons have nothing to do with key fingerprints.
Fingerprints are an issue for interoperability; GUI details are not.

---

From: "John W. Noerenberg" <[email-masked]>
Date: Wed, 14 Jul 1999 04:09:57 +0200

>are silver or gold should go through OpenPGP.

There are interesting points here.  If the word list is relied upon 
the the users of the application to exchange the fingerprint, then it 
is part of the protocol of key exchange.  While RFC2440 doesn't deal 
with key exchange, we've assumed that key verification by users would 
be performed by exchanging fingerprints in some fashion.  The word 
list  is an example of "in some fashion", and must equate to the 
fingerprint, otherwise it wouldn't unambiguously identify a key.

It is mandatory that any RFC2440 implementation generate and parse a 
particular kind of fingerprint.  While the word list may prove to be 
eminently useful (it may not, I was amused by Thomas' notion of a 
"spoken" business card).  It seems to me we can safely put this aside.

It may become an issue, however, if work on key exchange protocols 
and experience with word lists indicates it will likely become widely 
accepted, and is a preferred way to express the fingerprint.  For 
now, I'd prefer to leave it aside and concentrate on verifying the 
status in implementations of existing MUSTs in 2440.

john noerenberg (in Oslo Jul 10-19, 1999)
[email-masked]
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