[HOKEY] 答复: Re: AD review of draft-ietf-hokey-erp-aak

Hi,Qin

> Hi, Stephen:
> Thank for your valuable review. 
> Here is my answer to the main issues I think and I skip most of 
> editorial issues or nits issues. 
> My coauthors will address the remaining issues.
> ----------------------------------------
> #7, p5 - "The rIK is used to protect this message." Is that right?
> How is rIK used to protect the message when the message contain
> rIK?  I also wondered what "protect" means exactly - are the flags
> etc. all protected and how? 
> 
> [Qin] I think rIK should be corrected as pIK. pIK is used to protect
> the ERP message
> exchanged between the peer and the EA server. MSK used for normal 
> EAP exchange should be further derived into
> other child keys. Alternatively, the pMSK can be derived into child 
> keys. These child keys protect the ERP 
> message exchanged between the peer and SAP.

I reviewed this darft, and IMO it may be OK to let rIK unchanged,
since your are encapsulating AAK in ERP (am I right?), and ERP msgs are 
integrity protected
by rIK.
If changed to pIK, then it will another matter.

I am not sure what exactly is in your  mind.

Regards!

-Sujing Zhou

> 
> #8, p5 - If I'm an authenticated user and I send the message at
> step 2 to the SAP, then can I get the SAP to forward the message to
> anything on the Internet? If not, where does it say how that's
> controlled? I guess the SAP knows based on its config and/or the
> authentication state of the peer but if so you should probably say
> that?
> 
> [Qin]: SAP plays the role of authenticator should encapsulate the ERP 
message
> into AAA message and route the AAA message based on Realm part of 
KeyName-NAI.
> 
> #15, p8 - You can only have one keyName-NAI in the message and that
> MAY have either the home domain name or the domain name to which
> the peer is currently attached for ite realm part.  How does anyone
> know which to include when? Seems underspecified or missing a
> reference?
> 
> [Qin]: This was discussed on the list many times. Based on the 
discussion,
> we take the following way:
> The peer should know where to send the message? If the peer
> communicate with the home server, the peer should carry home domain name
> in the keyName-NAI. If the peer communicate with the local server, the 
peer
> should carry local domain name in the keyName-NAI.
> The authenticator or local ER server in the path can know if the 
> KeyName-NAI carry 
> local domain name by comparing the domain name carried in KeyName-
> NAI with local 
> domain name it has already known.
> 
> #16, p8 - How are CAP-Identifier and "Sequence number" TLVs
> "associated"?
> 
> [Qin]: Suppose multiple CAP-identifiers are carried in the ERP message,
> the same number of Sequence number TLVs should be carried with 
> associated CAP-identifier.
> We can rely on the order to associate each other.
> 
> #18, p8 - Exactly how is the sequence number used in the
> calculation of the pMSK for each CAP? Can these be re-used? (Across
> reboots?) Do they need to be random? That all needs stating I
> think.
> 
> [Qin]: This was discussed on the list before. The results is:
> If we carry three CAP-Identifiers, we should also send three 
> Sequence number TLVs 
> with associated CAP-Identifiers. The Sequence number for each CAP 
> MUST not be reused.
> 
> #20, p8 - authentication tag - where is the input to the HMAC
> function specified? (Its not here anyway.) I think someone needs to
> say how this is calculated. That means both the plaintext (message)
> input (e.g. are any header bits in/excluded?) and the key input
> (which key?). It could be that this just needs a reference if its
> done the same as some other RFC. An example would be great to give.
> 
> [Qin]: We should base on HMAC mechanims specified in RFC2104,
> Use the integrity algorithm indicated in the Cryptosuite field to 
> calculate authentication tag value. rIK will be used for calculation.
> The message used to calculate authentication tag should exclude 
authentication
> tag field and but not exclude header bits.
> 
> #22, p8 - You need references for the HMAC functions.
> 
> [Qin] It should be RFC2104.
> 
> #23, p8 - Should/are the choices for cryptosuites in some IANA
> registry?  If not, why not? If so, where?
> 
> [Qin] RFC5296 has already created registries for'Re-authentication
>    Cryptosuites'. These crytosuites can be reused for ERP-AAK.
> 
> #36, p11 - Is it ok for "different sequence numbers" to mean "just
> increment" or not?  Is it ok for sequence numbers to be re-used say
> after the peer reboots?  I think you need to say. 
> 
> [Qin] See the above answer to #16, #18.
> 
> 
> Regards!
> -Qin
> ----- Original Message ----- 
> From: "Stephen Farrell" <stephen.farrell@cs.tcd.ie>
> To: <hokey@ietf.org>
> Sent: Tuesday, November 22, 2011 2:39 AM
> Subject: [HOKEY] AD review of draft-ietf-hokey-erp-aak
> 
> 
> > 
> > Hi all,
> > 
> > Here's my review of this. There are a lot of comments,
> > but quite a few are very nitty or are things where I
> > probably just need to be told that I don't know enough
> > about ERP. (Which is true of course:-)
> > 
> > Some are non trivial however, and there are a lot of nits,
> > so I've put this into the revised-ID-needed state.
> > 
> > Probably best is to handle any easy ones via email and
> > then setup a skype chat for whatever's left. Let me
> > know...
> > 
> > Cheers,
> > S.
> > 
> >
> 
> 
> 
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