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 the resulting RFCs is to enable and encourage simpler and more rapid deployment of IPsec in contexts where use of unauthenticated SAs is deemed 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 particular
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 appropriate
c) If necessary, specify standards-track IKE extensions or profiles that support one or both of the bare RSA keys or self-signed certificates
d) Specify standards-track extensions to the SPD and PAD to support unauthenticated SAs for IPsec and cryptographic channel bindings for IPsec
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.
Milestones
Date
Milestone
Associated documents
Nov 2007
Submit IPsec interfaces draft to the IESG
Nov 2007
Recharter or close the WG
Oct 2007
WG LC on IPsec interfaces draft
Mar 2007
Submit IKE extensions to the IESG
Feb 2007
WG LC on IKE extensions (c)
Done milestones
Date
Milestone
Associated documents
Done
Submit SPD and/or PAD extensions to the IESG
Done
WG LC on SPD and/or PAD extensions (d)
Done
First version of IPsec interfaces draft (e)
Done
Submit problem and applicability statement to IESG (a+b)
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)