Re: [Hipsec] Spencer Dawkins' No Objection on draft-ietf-hip-dex-06: (with COMMENT)

2019-06-26 Thread Mirja Kuehlewind
Hi Miika,

Thanks for addressing these comments. Spencer is not serving in the AD role 
anymore, so I had a quick look at your feedback and believe this all looks good!

Regarding the question about SHOULDs: I don’t think it is necessary to go back 
and compare to RFC7401, however, a less time consuming effort could be to grab 
for all SHOULDs and shoulds and double-check if a) normative or non normative 
language should be used and b) if any clarification can or should be added to 
why this is a SHOULD and not a MUST. However I leave it to you (and the 
responsible AD) to make the final decision here!

Mirja
 

> On 19. Jun 2019, at 14:14, Miika Komu  wrote:
> 
> Hi,
> 
> ma, 2018-05-21 kello 17:52 -0700, Spencer Dawkins kirjoitti:
>> Spencer Dawkins has entered the following ballot position for
>> draft-ietf-hip-dex-06: No Objection
>> 
>> When responding, please keep the subject line intact and reply to all
>> email addresses included in the To and CC lines. (Feel free to cut
>> this
>> introductory paragraph, however.)
>> 
>> 
>> Please refer to 
>> https://www.ietf.org/iesg/statement/discuss-criteria.html
>> for more information about IESG DISCUSS and COMMENT positions.
>> 
>> 
>> The document, along with other ballot positions, can be found here:
>> https://datatracker.ietf.org/doc/draft-ietf-hip-dex/
>> 
>> 
>> 
>> ---
>> ---
>> COMMENT:
>> ---
>> ---
>> 
>> I'm not an expert on what people expect about security, but I'm
>> wondering if
>> there's a little too much distance between this text in the Abstract,
>> 
>>  This document specifies the Host Identity Protocol Diet EXchange
>> (HIP
>>   DEX), a variant of the Host Identity Protocol Version 2
>> (HIPv2).  The
>>   HIP DEX protocol design aims at reducing the overhead of the
>> employed
>>   cryptographic primitives by omitting public-key signatures and
>> hash
>>   functions.  In doing so, the main goal is to still deliver similar
>>   security properties to HIPv2.
>> 
>> and this text in the Introduction,
>> 
>>  The main differences between HIP BEX and HIP DEX are:
>> 
>> (snip)
>> 
>>  2.  HIP DEX forfeits the HIPv2 Perfect Forward Secrecy property of
>>   HIPv2 due to the removal of the ephemeral Diffie-Hellman key
>>   agreement.
>> 
>> Would the average reader consider "no PFS" to be similar to PFS?
>> (Please note that I'm not questioning the choice made in DIX, only
>> the way that
>> choice is described in the Abstract)
> 
> I agree that "similar" is very ambiguous. I have removed the sentence
> "In doing so, the main goal is to still deliver similar security
> properties to HIPv2" from the abstract (as suggested offline by Eric
> Vyncke). I hope this resolves your comment?
> 
>> I'm curious about whether a couple of other differences named in the
>> Introduction would also qualify as similar, but let's start with PFS.
>> 
>> I'm also curious about whether
>> 
>> 1.1.  The HIP Diet EXchange (DEX)
>> 
>> (snip)
>> 
>>   HIP DEX does not have the option to encrypt the Host Identity of
>> the
>>   Initiator in the 3rd packet.  The Responder's Host Identity also
>> is
>>   not protected.  Thus, contrary to HIPv2, HIP DEX does not provide
>> for
>>   end-point anonymity and any signaling that indicates such
>> anonymity
>>   should be ignored.
>> 
>> qualifies as "similar", but I don't have a good sense of how much
>> this matters
>> in current and expected HIP deployments.
> 
> the sentence has been removed from the abstract, I hope this point is
> also moot now.
> 
>> I'm hardly the smart one about this, but is
>> 
>>  o  HIP DEX lacks the Perfect Forward Secrecy (PFS) property of
>> HIPv2.
>>  Consequently, if an HI is compromised, all HIP connections
>>  protected with that HI are compromised.
>> 
>> correct? I was expecting to see something like "if an HI is
>> compromised, all
>> previous HIP connections protected with that HI are compromised".
> 
> you are correct, fixed.
> 
>> The version of this draft I'm reviewing has 57 occurrences of the
>> word
>> "should". I'm not seeing very many cases where the surrounding text
>> explains
>> why an implementation would not do what it SHOULD do, and I'm not
>> seeing many
>> cases where the surrounding text explains what the peer
>> implementation should
>> do, if the other endpoint doesn't do what it SHOULD do, although many
>> of those
>> cases might be captured in the state diagrams in the document.
> 
> many of the SHOULDs are inherited from the text in RFC7401. If you
> really want to, I can do a side by side comparison and check which ones
> are really new, and then improve the new ones? With my current
> priorities at work, this will unfortunately take a lot of time. Another
> way to resolve your comment is to add some general statement about the
> SHOULDs in the specification.
> 
>> In this text,
>> 
>>  By eliminating the need for 

Re: [Hipsec] Spencer Dawkins' No Objection on draft-ietf-hip-dex-06: (with COMMENT)

2019-06-19 Thread Miika Komu
Hi,

ma, 2018-05-21 kello 17:52 -0700, Spencer Dawkins kirjoitti:
> Spencer Dawkins has entered the following ballot position for
> draft-ietf-hip-dex-06: No Objection
> 
> When responding, please keep the subject line intact and reply to all
> email addresses included in the To and CC lines. (Feel free to cut
> this
> introductory paragraph, however.)
> 
> 
> Please refer to 
> https://www.ietf.org/iesg/statement/discuss-criteria.html
> for more information about IESG DISCUSS and COMMENT positions.
> 
> 
> The document, along with other ballot positions, can be found here:
> https://datatracker.ietf.org/doc/draft-ietf-hip-dex/
> 
> 
> 
> ---
> ---
> COMMENT:
> ---
> ---
> 
> I'm not an expert on what people expect about security, but I'm
> wondering if
> there's a little too much distance between this text in the Abstract,
> 
>   This document specifies the Host Identity Protocol Diet EXchange
> (HIP
>DEX), a variant of the Host Identity Protocol Version 2
> (HIPv2).  The
>HIP DEX protocol design aims at reducing the overhead of the
> employed
>cryptographic primitives by omitting public-key signatures and
> hash
>functions.  In doing so, the main goal is to still deliver similar
>security properties to HIPv2.
> 
> and this text in the Introduction,
> 
>   The main differences between HIP BEX and HIP DEX are:
> 
> (snip)
> 
>   2.  HIP DEX forfeits the HIPv2 Perfect Forward Secrecy property of
>HIPv2 due to the removal of the ephemeral Diffie-Hellman key
>agreement.
> 
> Would the average reader consider "no PFS" to be similar to PFS?
> (Please note that I'm not questioning the choice made in DIX, only
> the way that
> choice is described in the Abstract)

I agree that "similar" is very ambiguous. I have removed the sentence
"In doing so, the main goal is to still deliver similar security
properties to HIPv2" from the abstract (as suggested offline by Eric
Vyncke). I hope this resolves your comment?

> I'm curious about whether a couple of other differences named in the
> Introduction would also qualify as similar, but let's start with PFS.
> 
> I'm also curious about whether
> 
> 1.1.  The HIP Diet EXchange (DEX)
> 
> (snip)
> 
>HIP DEX does not have the option to encrypt the Host Identity of
> the
>Initiator in the 3rd packet.  The Responder's Host Identity also
> is
>not protected.  Thus, contrary to HIPv2, HIP DEX does not provide
> for
>end-point anonymity and any signaling that indicates such
> anonymity
>should be ignored.
> 
> qualifies as "similar", but I don't have a good sense of how much
> this matters
> in current and expected HIP deployments.

the sentence has been removed from the abstract, I hope this point is
also moot now.

> I'm hardly the smart one about this, but is
> 
>   o  HIP DEX lacks the Perfect Forward Secrecy (PFS) property of
> HIPv2.
>   Consequently, if an HI is compromised, all HIP connections
>   protected with that HI are compromised.
> 
> correct? I was expecting to see something like "if an HI is
> compromised, all
> previous HIP connections protected with that HI are compromised".

you are correct, fixed.

> The version of this draft I'm reviewing has 57 occurrences of the
> word
> "should". I'm not seeing very many cases where the surrounding text
> explains
> why an implementation would not do what it SHOULD do, and I'm not
> seeing many
> cases where the surrounding text explains what the peer
> implementation should
> do, if the other endpoint doesn't do what it SHOULD do, although many
> of those
> cases might be captured in the state diagrams in the document.

many of the SHOULDs are inherited from the text in RFC7401. If you
really want to, I can do a side by side comparison and check which ones
are really new, and then improve the new ones? With my current
priorities at work, this will unfortunately take a lot of time. Another
way to resolve your comment is to add some general statement about the
SHOULDs in the specification.

> In this text,
> 
>   By eliminating the need for public-key signatures and the ephemeral
>DH key agreement, HIP DEX reduces the computation, energy,
>  
>transmission, and memory requirements for public-key cryptography
>^
>(see [LN08]) in the HIPv2 protocol design.  Moreover, by dropping
> the
>cryptographic hash function, HIP DEX affords a more efficient
> 
>protocol implementation than HIP BEX with respect to the
>^^^
>corresponding computation and memory requirements.
> 
> is "efficient" the right word, in the second sentence? This seems to
> mirror
> that "reducing requirements" effect from the first sentence - I'd
> assume that
> if