Subject: Arcfour & RC4

From: Chris Lonvick <[email-masked]>
Date: Wed, 9 Mar 2005 12:49:09 -0800 (PST)

Hi,

I went to the IPR WG meeting on Monday and learned lots.  But enough about
me...

The current [TRANS] document references Arcfour as an acceptable
algorithm.  It also references RC4 in a somewhat oblique way as follows:

   The "arcfour" is the Arcfour stream cipher with 128 bit keys.  The
   Arcfour cipher is believed to be compatible with the RC4 cipher
   [SCHNEIER].  Arcfour (and RC4) has problems with weak keys, and
   should be used with caution.

The parts about RC4 sound editorial to me.  I also don't think that the
document should say that there is a "belief" in compatability; they either
are provably compatible, or the document should remain silent on that
point.  As such, I propose to change the text to the following:

   The "arcfour" cipher is the Arcfour stream cipher with 128 bit keys
   [SCHNEIER].  Arcfour has problems with weak keys, and should be used
   with caution.

Please let me know if you disagree with this proposal.

Thanks,
Chris

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From: Sam Hartman <[email-masked]>
Date: Wed, 09 Mar 2005 16:45:27 -0500

I think it is valuable to point out to people that arcfour is rc4.

---

From: Rodney Thayer <[email-masked]>
Date: Wed, 09 Mar 2005 15:00:24 -0800

This is an artifact of history.

Arcfour was brought into the IETF world back in the TLS days.  The folks 
at SSH and I coded ARCFOUR, from Schneier, so that we'd have a copy of 
the algorithm that wasn't tied up inside the RSA intellectual property.

The term "RC4" is trade marked by RSA.  The algorithm leaked into the 
public domain several years ago, in effect
(#include <I-am-not-a-lawyer.h>)

The text you refer to sounds like the ARCFOUR draft from way back when ;-)

---

From: Chris Lonvick <[email-masked]>
Date: Wed, 9 Mar 2005 15:44:29 -0800 (PST)

Hi Rodney,

Can you tell me why draft-kaukonen-cipher-arcfour-03.txt expired rather
than being published as an RFC?  IANAL either.

Thanks,
Chris

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From: Rodney Thayer <[email-masked]>
Date: Wed, 09 Mar 2005 16:18:27 -0800

Basically because there was no clear mechanism at the time to get it to 
informational.  The IETF has been a rat's nest of arcane, undocumented, 
and inconsistent procedures, of course, and it is apparently getting 
better, but at the time we couldn't figure out how to get it to RFC status.

That's the vulnerability in the IETF - it's easier to route around it 
than work through it.

---

From: Chris Lonvick <[email-masked]>
Date: Wed, 9 Mar 2005 18:04:03 -0800 (PST)

Hi,

Then I'll go with the advice given by our AD and Jeffrey; no changes to
the IDs for this.  As there is a process to produce an Informational RFC
now, (and we're kind'a cooling our heels for the moment,) would you
consider resurrecting cipher-arcfour?  It's still viable and would be a
good reference for this and other efforts.

I agree that the IETF process is improving - we're becoming an
acknowledged Standards Developing Organization (SDO).

Thanks,
Chris

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From: Jeffrey Hutzelman <[email-masked]>
Date: Wed, 09 Mar 2005 16:47:34 -0500

On Wednesday, March 09, 2005 12:49:09 -0800 Chris Lonvick 
<[email-masked]> wrote:

> point.

This is actually pretty standard boilerplate for this situation.

I see no reason to make this change.

-- Jeff

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From: Ben Harris <[email-masked]>
Date: Thu, 10 Mar 2005 11:13:25 +0000

In article <[email-masked]> you write:
>As such, I propose to change the text to the following:
>

I disagree.  The term "Arcfour" doesn't appear anywhere in [SCHNEIER] -- he
calls it RC4.  Thus, if we're referencing [SCHNEIER] for it, we need to
mention the name RC4 as well.  The current text isn't perfect, but it's good
enough.

-- 
Ben Harris