Re: [Ace] Review draft-ietf-ace-coap-est

[Peter van der Stok <[e-mail]>]

Hi Jim, 

Many thanks for the review. See our answers below.

* In section 4.1 I have a question about what you are using for payload
content encoding.  Part of this might just be a question of how you plan
to move from ASN.1 to CBOR at some point in the future.  I think that it
would necessitate doing new media-types in that event.  You appear to be
doing a CBOR bstr wrapping on the ASN.1 encoding payload.  I don't
believe that there is any reason for doing this.  I would expect that
the payload would be the ASN.1 w/o any ASN.1.  It is highly possible
that I am just mis-reading what the text says and this is what you say. 

<pvds> 

What I wanted to do, and did not express very well. 

Keep the ASN.1 structure of the payload; (re-using code) 

Use straight binary coding instead of the base64-encoded (30% payload
reduction) 

Wrap the binary in a CBOR major type 2 h'xxx' notation. (compatibility
with multipart) 

Not sure if this needs a new media type, the http content-coding and
transfer-coding registries were not very helpful. 

</pvds>

* In section 5.0 - As written, the example of doing a query against
/.well-known/core does not match my understanding of what would be
return.
It should only return those resources which have the rt field set on
them.
I do not understand why you believe that the following lines MAY be
returned.  Clarification of why you think this is true would be
appreciated. 

<pvds> 

Thanks for your reaction, I hesitated between two choices. 

 	* Provide every line with another rt=ace.est.crts; rt=ace.est.sen;
etc.
 	* Make them all ace.est.

There are no structure guidelines on rt= value, which complicates
things. 

Looking forward to your (and others) opinion. 

</pvds>

* Section 6 - Is there a need to have all of this description around
TLS-unique?  Do you have a reason to believe that people are going get
this implemented wrong? 

<pan>
This come from experience. The implementation we had done in the past
did not implement it correctly, that is why we expanded on the
TLS-unique. We will see about shrinking the text in the draft.  

</pan>

* Section 7 - I think the figure has an error associated w/ it.  The CA
should be tied to the EST Server and not to the Registrar 

<pan>
Thank you, we will fix that in the next iteration. 

</pan>

* Section 7 - Your language is a bit sloppy around the terms of POP and
POP linking.  Unless it is really badly behaved, POP should never be
broken by an RA.  The POP is the signature on the request and not tied
to the TLS channel.  The POP linking is tied to the TLS channel and is
broken by the changing of the TLS sessions (client <-> RA,  RA <-> CA)  

<pan>
Very good catch. We will tighten the language in the next iteration. 

</pan>

* Section 7 - It is not clear to me that the SHOULD on reassembly of
fragmentation is not a MUST.  I doubt that any EST server is going to be
able to deal with getting fragments of requests from a registrar in
separate messages.  This would be compounded if the proxy is handling
multiple sessions at the same time.  

<pan>
I think that is reasonable. We will address it.  

</pan>

* Section 7 - It should be possible that when doing key generation for
the protection of the private key to be end-to-end and it should not be
necessary for the Proxy to decrypt and then re-encrypt the private key. 
It should not matter for this if one does either symmetric or asymmetric
encryption of the private key. 

<pvds> 

Proxy: you mean Registrar. 

The wish is understood, we'll look into it. 

</pvds>

* Section 7 - It is very possible that the private key generation
function would be hosted on the proxy and not at the CA.  I think that
you might want to describe this as a normal configuration.  (Just
spotted this in the Security considerations.  I think it should be here
as well.) 

<pan>
Yes, right. We need to be crisper on the document that end to end or
proxy can provide this functionality. We will make sure it is clear in
the text.  

</pan>

* Section 9.1 - application/multipart-core should not be in the table of
items for IANA to register.  This is being done in a different document.
 If you want this table as a whole then it needs to be moved out of IANA
considerations. 

<pvds> 

Absolutely right. Content-format is also specified I multipart-ct; did
not see that. Will remove the entry. 

</pvds>

* Section 9.2 - please expand this text some.  You might want to look at
https://tools.ietf.org/html/rfc7390#section-6.1 for a template. 

<pvds> 

Will do 

</pvds> 

Thanks Jim, This really helps to improve the document 

Peter, Panos

Jim Schaad schreef op 2018-07-01 15:33:

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