Better-Than-Nothing Security (btns) Concluded WG

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WG Name Better-Than-Nothing Security
Acronym btns
Area Security Area (sec)
State Concluded
Charter charter-ietf-btns-03 Approved
Dependencies Document dependency graph (SVG)
Personnel Chairs Julien Laganier
Love Astrand
Mailing list Address
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Charter for Working Group

Current Internet Protocol security protocol (IPsec) and Internet Key
Exchange protocol (IKE) present somewhat of an all-or-nothing
alternative; these protocols provide protection from a wide array of
possible threats, but are sometimes not deployed because of the need
for pre-existing credentials. There is significant interest in
providing anonymous (unauthenticated) keying for IPsec to create
security associations
(SAs) with peers who do not possess authentication credentials that
can be validated. Examples of such credentials include self-signed
certificates or "bare" public keys. This mode would protect against
passive attacks but would be vulnerable to active attacks.

The primary purpose of this working group is to specify extensions to
the IPsec architecture, and possibly extensions or profiles of IKE, so
that IPsec will support creation of unauthenticated SAs. The goal of
resulting RFCs is to enable and encourage simpler and more rapid
deployment of IPsec in contexts where use of unauthenticated SAs is
appropriate, to enable and encourage the use of network security where
it has been difficult to deploy--notably, to enable simpler, more
rapid deployment.

Any IKE and IPsec extensions/profiles developed in this WG must not
undermine the security facilities already defined for IPsec.
Specifically, the access control facilities that are central to IPsec
must not be degraded when unauthenticated SAs are employed
concurrently with authenticated SAs in the same IPsec implementation.

Two related problems emerged during the discussion of this problem.
First, there is a desire in the KITTEN, RDDP, NFSv4 and potentially
other working groups to make use of unauthenticated IPsec SAs, and
later cryptographically bind these SAs to applications, which perform
their own authentication. The specification of how this binding is
performed for IPsec and the specification of how the binding interacts
with application authentication protocols are out of scope for this
working group. However, interactions between this cryptographic
channel binding and IPsec (e.g., the PAD, SPD, SAD, etc.) are expected
to be similar to those for the unauthenticated mode with no
binding. To avoid duplication of effort, This working group needs to
consider how to support channel bindings when developing extensions to
IPsec, specifically the PAD and SPD elements.

Secondly, BTNS and the channel bindings work both encourage IPsec to
be used to secure higher layer protocols. As such we need to determine
what information these higher layer protocols need from IPsec.

Two proposals are under discussion for providing unauthenticated SA
support for IPsec: bare RSA keys transported by IKE and self-signed
certificates transported by IKE.

The WG has the following specific goals:

a) Develop an informational framework document to describe the
motivation and goals for having security protocols that support
anonymous keying of security associations in general, and IPsec and
IKE in

b) Develop an informational applicability statement, describing a set
of threat models with relaxed adversary capability assumptions, to
characterize the contexts in which use of unauthenticated SAs is

c) If necessary, specify standards-track IKE extensions or profiles
that support one or both of the bare RSA keys or self-signed

d) Specify standards-track extensions to the SPD and PAD to support
unauthenticated SAs for IPsec and cryptographic channel bindings for

e) Develop an informational document describing the interfaces that
IPsec implementations should provide to allow IPsec SAs to be used to
secure higher layer protocols

The final goal is expected to complement work going on elsewhere in
establishing best current practice for higher layer protocols secured
by IPsec.


Date Milestone
Nov 2007 Recharter or close the WG
Nov 2007 Submit IPsec interfaces draft to the IESG
Oct 2007 WG LC on IPsec interfaces draft
Done Submit SPD and/or PAD extensions to the IESG
Mar 2007 Submit IKE extensions to the IESG
Done WG LC on SPD and/or PAD extensions (d)
Feb 2007 WG LC on IKE extensions (c)
Done Submit problem and applicability statement to IESG (a+b)
Done First version of IPsec interfaces draft (e)
Done WG LC on problem and applicability statement (a+b)
Done First version of IKE extensions draft (if needed)
Done First version of SPD and/or PAD extensions draft (if needed)
Done First version of problem and applicability statement (a+b)
Done Confirm on mailing list whether SPD and/or PAD extensions are needed (d)