On 3/25/14 11:33 , "t.petch" <[email protected]> wrote:

>I am confused by your choice of names.  The text uses, e.g.,
>usmHMACSHA224128AuthProtocol
>
>whereas the MIB module has
>
> usmHmacSha224128Protocol
>
>Do these refer to the same identity (times six)?

I think yes, and would suggest the following (unified) name format:

usmHMAC128SHA224AuthProtocol


for all of them.

>I think that the IANA Considerations needs more work; you might want to
>review RFC4181 for a more detailed approach but you need at least
>something along the lines of an explicit request that the MIB module be
>assigned a number under the appropriate tree, e.g.,..............

I'll leave this to Johannes to take care of. :-)

>And then there are Security Considerations.  You are replacing a simple,
>well understood choice of two values with a choice of eight, and saying
>that there is no need to implement them all.  This gives great scope for
>a lack of interoperability.  Should there be a mandatory to implement
>value (or negotiation - perhaps not)?

Can we have mandatory-to-implement in an "optional" RFC? Assuming the
answer is yes, I'd recommend:

For those who implement this RFC, usmHMAC192SHA256AuthProtocol is MUST,
usmHMAC384SHA512AuthProtocol is SHOULD, everything else is MAY. Unless
there's a preference for the "non-truncated" algorithms.

>I would like to see some discussion of the benefits, if any, of the six
>new options.

Do you mean "the benefits of having so many rather than just one or two",
or do you mean "the benefits of adding SHA2-based auth"?

If it's the first - then we probably can shrink the number of the
available choices. The question is - do we select truncated ones (as the
prior standards did), or not?

If it's the second - I'll let others speak. :-)


>I have seen discussions along these lines on the TLS WG
>list (with a considerable degree of expertise in cryptography present)
>that makes it far from clear cut what the best choice is, and that what
>appears to be the strongest may not be a good choice for IETF protocols.

Honestly I don't think TLS WG is a good example here, considering the
complexity of the protocol, and the kind of problems they're facing and
are trying to address. But your point is taken.

TNX!


>----- Original Message -----
>From: "Johannes Merkle" <[email protected]>
>To: <[email protected]>
>Cc: "Manfred Lochter" <[email protected]>; <[email protected]>
>Sent: Monday, March 24, 2014 12:35 PM
>Subject: [OPSAWG] Fwd: New Version Notification
>fordraft-hmac-sha-2-usm-snmp-00.txt
>
>
>> Dear all,
>>
>> a while ago, I had announced a draft on a new USM authentication
>protocol HMAC-SHA-256-128 for use in SNMP. Following
>> Uri's suggestion (and with his valuable support) I have considerably
>extended the draft:
>>  - Further SHA-2 based HMAC authentication protocols have been
>included to provide ore flexibility.
>>  - A (short) section explains how to perform key change and key
>localization with these protocols
>>  - A MIB definition has been added.
>>
>> URL:
>http://www.ietf.org/internet-drafts/draft-hmac-sha-2-usm-snmp-00.txt
>> Status:
>https://datatracker.ietf.org/doc/draft-hmac-sha-2-usm-snmp/
>> Htmlized:
>http://tools.ietf.org/html/draft-hmac-sha-2-usm-snmp-00
>>
>>
>> Abstract:
>>    This memo specifies new optional HMAC-SHA-2 authentication
>protocols
>>    for the User-based Security Model (USM) for SNMPv3 defined in RFC
>>    3414.
>>
>>
>> Due to the extension of the draft to other SHA-2-based HMAC, I have
>changed the draft name from
>> draft-hmac-sha-256-128-usm-snmp
>> to
>> draft-hmac-sha-2-usm-snmp
>> resulting in a reset of the version number (00).
>>
>> Is there interest in adoption of this draft by the WG?
>>
>> Johannes
>>
>>
>> _______________________________________________
>> OPSAWG mailing list
>> [email protected]
>> https://www.ietf.org/mailman/listinfo/opsawg
>

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