Subject: [Ietf-krb-wg] I-D Action: draft-ietf-krb-wg-des-die-die-die-00.txt

From: [email-masked]
Date: Sun, 05 Feb 2012 12:49:45 -0800

A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the Kerberos Working Group of the IETF.

	Title           : Deprecate DES support for Kerberos
	Author(s)       : Love Hornquist Astrand
                          Tom Yu
	Filename        : draft-ietf-krb-wg-des-die-die-die-00.txt
	Pages           : 14
	Date            : 2012-02-03

   The Kerberos 5 network authentication protocol originally used the
   Data Encryption Standard (DES) for encryption.  Almost 30 years it
   introduced the first DES standard, the National Institute of
   Standards and Technology (NIST) finally withdrew the DES standard in
   2005, reflecting a long-established consensus that DES no longer
   provides adequate security.  In 2006, it cost less than EUR 10,000 to
   build a machine to brute force DES keys in an average of 8.7 days.
   By 2008, it was possible to buy commercial hardware that breaks DES
   keys in less than a day on average.  DES is long past its sell-by
   date.  Accordingly, this document updates RFC1964, RFC4120, and
   RFC4121 to deprecate the use of DES in Kerberos.  Because the
   original Kerberos 5 specification, RFC1510 (obsoleted by RFC 4120),
   supports only DES, this document also reclassifies RFC1510 as
   Historic.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-krb-wg-des-die-die-die-00.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

This Internet-Draft can be retrieved at:
ftp://ftp.ietf.org/internet-drafts/draft-ietf-krb-wg-des-die-die-die-00.txt

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From: Tom Yu <[email-masked]>
Date: Sun, 05 Feb 2012 21:51:25 -0500

This version is mostly editorial cleanup.  I also added updated
information about DES cracking performance -- it seems that one day
average per key was commercially available by 2008.  I think the
abstract could get shorter; any suggestions about what to cut?

Open items -- what other algorithms do we need to deprecate?
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From: "Henry B. Hotz" <[email-masked]>
Date: Sun, 5 Feb 2012 23:43:17 -0800

Hows much effort do we really need to put into this?  Everyone knows it needs to happen (and should have already).

1 day/key was before the Amazon Cloud.  I'd be curious what it costs in Cloud time now, but I wouldn't hold up the draft for it.

> Open items -- what other algorithms do we need to deprecate?

I thought 3-des supposed to be EOL last year, but I guess that was only 2TDEA.  Any checksum algorithms that are past date?

I wouldn't hold up this draft for other algorithms, but it's a good question.  If other stuff should get similar treatment we shouldn't be so slow about writing a similar draft.

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From: Tom Yu <[email-masked]>
Date: Mon, 06 Feb 2012 15:22:23 -0500

> Hows much effort do we really need to put into this?  Everyone knows it needs to happen (and should have already).

I think it's close to done.  (I noticed a word omission in the
abstract after I submitted it, and maybe more minor editing needs
doing.)  I'm not sure where we left the document state before.  Did we
do a WGLC on it?

> 1 day/key was before the Amazon Cloud.  I'd be curious what it costs in Cloud time now, but I wouldn't hold up the draft for it.

Yeah, having good current price/performance numbers would be nice, but
might take a while given that academic researchers are likely to think
that breaking DES is no longer interesting.

> I thought 3-des supposed to be EOL last year, but I guess that was only 2TDEA.  Any checksum algorithms that are past date?

I think the current document deprecates some of them already (though
mostly some bare unkeyed checksums).
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From: Tom Yu <[email-masked]>
Date: Mon, 06 Feb 2012 18:59:08 -0500

> doing.)  I'm not sure where we left the document state before.  Did we

Of course, now that I've submitted the draft, I've found a number of
small typos, and an occurrence of "DES-MD5" that really should be
"RSA-MD5".  Fixed in my working copy.  Also improved some citations
and shortened the Abstract a little.

> mostly some bare unkeyed checksums).

I also removed the section about "Other old enctypes".
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From: Jeffrey Hutzelman <[email-masked]>
Date: Tue, 07 Feb 2012 12:57:09 -0500

> > doing.)  I'm not sure where we left the document state before.  Did we

We did a WGLC in March of 2010; there was some additional discussion
around October.  I'm also not 100% sure that one of my review comments
at the time was addressed, which in fact was about...

> "RSA-MD5".

So, we want to eliminate RSA-MD5-DES, but I'm not sure we agreed to
eliminate the unkeyed RSA-MD5.  We certainly don't want to try to
eliminate "DES-MD5(7)", since there is no such thing.

See my message of 13-Aug-2010.

-- Jeff

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From: Tom Yu <[email-masked]>
Date: Wed, 08 Feb 2012 09:21:12 -0500

> eliminate "DES-MD5(7)", since there is no such thing.

I think we should say that implementations MAY RSA-MD5(7) but only in
an Authenticator, because it's additionally protected there.  There's
a paragraph that says that, but it could be more clear.

We should remove the reference to the nonexistent "DES-MD5(7)".
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