Subject: RE: [eap] Proposed Resolution of Issue 320: Use of term Lower Layer

From: "Salowey, Joe" <[email-masked]>
Date: Tue, 24 Jan 2006 23:32:32 -0800

This looks good to me.  

> -----Original Message-----
> From: Bernard Aboba [mailto:[email-masked]] 
> Sent: Monday, January 23, 2006 7:32 AM
> To: [email-masked]; [email-masked]
> Subject: RE: [eap] Proposed Resolution of Issue 320: Use of 
> term Lower Layer
> 
> One more:
> 
> Change the first two paragraphs of Section 2.2 to:
> 
> "As illustrated in Figure 3, on completion of EAP authentication, EAP 
> methods
> export the Master Session Key (MSK), Extended
> Master Session Key (EMSK), Peer-ID,
> Server-ID, Session-ID and Key-Lifetime to the EAP peer or 
> authenticator 
> layers.  The
> Initialization Vector (IV) is
> deprecated.
> 
> The EAP peer and authenticator layers MUST NOT modify or cache
> keying material or parameters (including Channel Bindings)
> passing in either direction between
> the EAP method layer and the EAP layer.
> The EAP layer also MUST NOT cache keying material or parameters
> (including Channel Bindings) passed to it, whether by the EAP 
> peer/authenticator
> layer, the lower layer or the AAA layer."
> 
> >Additional changes required to resolve this issue:
> >
> >Change:
> >
> >"Existing EAP lower layers handle the caching of EAP keying
> >material and the generation of transient session keys in
> >different ways:"
> >
> >To:
> >
> >"Existing EAP lower layers and AAA layers handle the caching 
> of EAP keying
> >material and the generation of transient session keys in
> >different ways:"
> >
> >Change "Lower Layer" to "Lower Layer or AAA" in Figure 3.
> >
> >>The text of Issue 320 is enclosed below.  The proposed 
> resolution is to 
> >>accept the changes, with modifications to one of the suggestions as 
> >>follows:
> >>
> >>Change
> >>
> >>"The exception to the "no sharing" rule is the AAA layer.  On EAP
> >>server, keying material requested by and passed down to the 
> AAA layer
> >>may be replicated to the AAA layer on the authenticator.   On the
> >>authenticator, the AAA layer may provide the replicated keying
> >>material to the lower layer over which the EAP authentication
> >>conversation took place.  This enables "mode independence" to be
> >>maintained. "
> >>
> >>To
> >>
> >>"On the EAP server, keying material requested by and passed 
> down to the 
> >>AAA layer
> >>may be replicated to the AAA layer on the authenticator.   On the
> >>authenticator, the AAA layer may provide the replicated keying
> >>material to the lower layer over which the EAP authentication
> >>conversation took place.  This enables "mode independence" to be 
> >>maintained.
> >>However, the EMSK MUST NOT be transported by the AAA layer."
> >>
> >>------------------------------------------------------------
> ---------------------------------------------------------
> >>Issue 320: Use of term lower layer
> >>Submitter name: Joe Salowey
> >>Submitter email address: [email-masked]
> >>Date Submitted: December 1, 2005
> >>Reference:
> >>Document: Keying-08
> >>Comment type: E
> >>Priority: 1
> >>Section: 2
> >>Rationale/Explanation of issue:
> >>The term lower layer is used inconsistently in the document.
> >>
> >>Lower layer should refer to the protocol between the EAP 
> Peer and the
> >>EAP Authenticator.  It is between these entities that the security
> >>association protocol is typically run.  The MSK is 
> transported to the
> >>lower layer.
> >>
> >>AAA is not an EAP lower layer except in the special case 
> where the AAA
> >>client and server are acting as the EAP Peer and EAP 
> Authenticator for
> >>some reason (an example of this could was in EUSM).  
> Entities other than
> >>the lower layer may obtain keys derived from the EMSK.
> >>
> >>Requested change:
> >>
> >>Section 2.1
> >>-----------
> >>change
> >>
> >>"Of these phases, Phase 0, 1b and Phase 2 are handled by a 
> lower layer."
> >>
> >>To
> >>
> >>"Of these phases, Phase 0, 1b and Phase 2 are handled 
> external to EAP.
> >>Phases 0 and 2 are handled by the lower layer protocol and 
> phase 1b is
> >>typically handled by a AAA protocol."
> >>
> >>Section 2.2
> >>------------
> >>(remove references to IV)
> >>---
> >>Change
> >>
> >>"The EMSK MUST NOT be provided to the lower layer, nor is 
> it permitted
> >>to pass any quantity to the lower layer from which the EMSK could be
> >>computed without breaking some cryptographic assumption, such as
> >>inverting a one-way function."
> >>
> >>To
> >>
> >>"The EMSK MUST NOT be provided to an entity outside the EAP 
> server or
> >>peer,  nor is it permitted to pass any quantity to an 
> entity outside the 
> >>EAP
> >>server or peer from which the EMSK could be computed 
> without breaking some 
> >>cryptographic assumption, such as
> >>inverting a one-way function."
> >>---
> >>Change
> >>
> >>"In order to preserve the security of keys derived within 
> EAP methods,
> >>lower layers other than AAA MUST NOT export keys passed down by EAP
> >>methods. "
> >>
> >>To
> >>
> >>"In order to preserve the security of keys derived within 
> EAP methods,
> >> lower layers MUST NOT export keys passed down by EAP
> >> methods."
> >>---
> >>Change
> >>
> >>"EAP keying material and parameters provided to a lower layer other
> >>than AAA MUST NOT be transported to another entity."
> >>
> >>To
> >>
> >>"EAP keying material and parameters provided to a lower 
> layer MUST NOT
> >>be transported to another entity."
> >>---
> >>Change
> >>
> >>"The exception to the "no sharing" rule is the AAA layer.  On EAP
> >>server, keying material requested by and passed down to the 
> AAA layer
> >>may be replicated to the AAA layer on the authenticator.   On the
> >>authenticator, the AAA layer may provide the replicated keying
> >>material to the lower layer over which the EAP authentication
> >>conversation took place.  This enables "mode independence" to be
> >>maintained. "
> >>
> >>To
> >>
> >>"The AAA layer may transport keys that are exported from 
> the EAP server.
> >>On the EAP server, keying material requested by and passed 
> down to the AAA 
> >>layer
> >>may be replicated to the AAA layer on the authenticator.   On the
> >>authenticator, the AAA layer may provide the replicated keying
> >>material to the lower layer over which the EAP authentication
> >>conversation took place.  This enables "mode independence" to be 
> >>maintained."
> >>
> >>-----------
> >>Section 2.3
> >>-----------
> >>
> >>Change
> >>"The caching behavior of existing EAP lower layers is as follows:"
> >>
> >>To
> >>
> >>"The caching behavior of existing EAP lower layers and AAA 
> layers is as
> >>follows:"
> >>
> >>
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> 
> 
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