Dr. Rafiee-

In reading your ID, I didn't see a mechanism for ensuring a central 
certification authority like in PKI (eg a CA) like used in SeND/CGA.  How can 
hosts trust the signed NDP messages?  Or is this ID meant to be another option 
to CGA not necessarily a replacement for SeND?



010100110110010101101101011100000110010101110010001000000100011001101001

Jeremy Duncan
Senior Director, IPv6 Network Architect
Salient Federal Solutions, Inc. (Now including SGIS & Command Information Inc.)
4000 Legato Road, Suite 600
Fairfax, VA 22033
Google Voice: 540.440.1193
jeremy.dun...@salientfed.com

Hosnieh Rafiee <i...@rozanak.com> wrote:


Thanks for your comments.

-----Original Message-----
From: Fernando Gont [mailto:fg...@si6networks.com]
Sent: Saturday, January 05, 2013 11:32 PM
To: Hosnieh Rafiee
Cc: ipv6@ietf.org
Subject: Re: Call for comments on draft-rafiee-6man-ssas-00.txt

Hosnieh,

I've reviewed the I-D till Section 3 (didn't get into 3.1)... but it looks
like the I-D got some things wrong....

Please see in-line...


> Abstract
>
>    The default method for IPv6 address generation uses two unique
>    manufacturer IDs that are assigned by the IEEE Standards Association
>    [1] (section 2.5.1 RFC-4291) [RFC4291].

What are the two IDs assigned by the IEEE?



>    This means that a node will
>    always have the same Interface ID (IID) whenever it connects to a new
>    network. Because the node's IP address does not change, the node is
>    vulnerable to privacy related attacks.

The IP address does change. It's only the IID part that usually doesn't.



>    To address this issue, there
>    are currently two mechanisms in use to randomize the IID,
>    Cryptographically Generated Addresses (CGA) [RFC3972] and Privacy
>    Extension [RFC4941].

This is incorrect. CGAs are meant to solve a different problem. Privacy
Addresses do (partially) mitigate this issue.



>    The problem with the former approach is the
>    computational cost involved for the IID generation.

No. The problem with CGAs are:

* IPRs

* Requirement for a PKI with SEND (which is where CGAs are used)

* Small ROI (complexity to implement, complexity to deploy, small number of
implementations)... all to solve a problem we have lived with in the
IPv4 world for years... and unless you solve other problems (e.g., unsecured
DNS), it doesn't make much sense to bother with SEND.



>    The problem with
>    the latter approach is that it lacks security. This document offers a
>    new algorithm for use in the generation of the IID while, at the same
>    time, securing the node against some types of attack, such as IP
>    spoofing. These attacks are prevented with the addition of a
>    signature to the Neighbor Discovery messages (NDP).

If you just sign the NDP messages, you're not mitigating spoofing -- how
would a non-local host authenticate the packet, if the signatures are in NDP
messages (which are only local)?


> 1.  Introduction
>
>    IPv6 addresses consist of two parts; the subnet prefix, which is
> the

Global routing prefix, subnet ID, Interface ID

(in the case of GUAs, of course)



>    which is the 64 rightmost bits of IPv6 address. The IEEE Standards
>    Association [1] (section 2.5.1 RFC-4291) [RFC4291] offered a standard
>    for the generation of the IPv6 Interface IDs (IID).

The IEEE does not standardize IPv6.


>    They are
>    generated by the concatenation of an Extended Unique Identifier
>    (EUI-64) with an Organizationally Unique Identifier (OUI),

EUI-64 includes the OUI.


>    both of
>    which are assigned by the IEEE Registration Authority (IEEE RA). For
>    example, if a manufacturer's OUI-36 hexadecimal value is
>    00-5A-D1-02-3, and the manufacture hexadecimal value for the
>    extension identifier for a given component is 4-42-61-71,

The latter is assigned by the vendor, not by the IEEE.



>    EUI-64 value generated from these two numbers will be
>    00-5A-D1-02-34-42-61-71. There are two mechanisms used to randomize
>    the IID; CGA [RFC3972] and Privacy Extension [RFC4941].

Please clarify what you mean by "randomize".


> 3.  Problem Statement
>
>    The drawback to the IEEE Standards Association approach for the
>    generation of the IID is one of privacy.

That's an *IETF* approach, not IEEE's.



>    The main problem with the privacy extension mechanism, when using the
>    first approach, as explained in section 3.2.1 RFC-4941 [RFC4941] ,
>    i.e., using stable storage, is the lack of a provision for use of a
>    security mechanism.

Not sure what you mean by "lack of a provision for use of a security
mechanism.".



>    A Privacy extension can prevent attacks related
>    to privacy issues,

We have already gone through this one: Privacy addresses only
*partially* mitigate host-tracking attacks.

Thanks,
--
Fernando Gont
SI6 Networks
e-mail: fg...@si6networks.com
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492




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