Hello All,

I was invited into this list because I had some questions.  I am not able to 
contribute anything so would someone be so kind as to remove me from this list. 
 My email is michael.kelly.49....@us.af.mil

Thank you for your time,
M Bryan Kelly
JT3/ATAC Contractor
412 TENG/ENIE CANIS Software
DSN 527-7852
Blg 1600 Block 500
300 E. Yeager Blvd
Edwards AFB, 93524

-----Original Message-----
From: ietf [mailto:ietf-boun...@ietf.org] On Behalf Of Dan Romascanu
Sent: Tuesday, February 13, 2018 2:44 AM
To: gen-...@ietf.org
Cc: lwip@ietf.org; droma...@gmail.com; i...@ietf.org; 
Subject: [Non-DoD Source] Genart last call review of 

Reviewer: Dan Romascanu
Review result: Ready with Issues

I am the assigned Gen-ART reviewer for this draft. The General Area Review Team 
(Gen-ART) reviews all IETF documents being processed by the IESG for the IETF 
Chair.  Please treat these comments just like any other last call comments.

For more information, please see the FAQ at


Document: draft-ietf-lwig-crypto-sensors-05
Reviewer: Dan Romascanu
Review Date: 2018-02-13
IETF LC End Date: 2018-02-19
IESG Telechat date: 2018-02-22


This is a well-written clear informational memo, documenting methods to secure 
networks built of resource-constrained devices. It describes a deployment model 
based on exchanges of signed objects, and documents available cryptographic 
libraries that may be suited to the targets. The conclusions include analysis 
of trade-offs and recommendations for future development and deployments.

The document is READY from Gen-ART perspective. There are a couple of 
non-blocking issues that I would be glad to have them clarified before 
approval. I have also pointed to a couple of nits.

Major issues:

Minor issues:

1. In Section 7:

'The location of the resource directory was configured into
   the smart object sensor by hardcoding the IP address'

Is this reasonable? I understand that the goal of the exercise was to 
demonstrate that it is possible to implement the entire architecture with 
public-key cryptography on an 8-bit micro-controller, but hard-coding the IP 
address seems to be below the threshold of a functional system. IMO there is a 
need to be able for the sensor to acquire this address (DHCP stack, or a simple 
UI to stream in one address, etc.)

2. In section 8.1 - I would expect some discussion about the extra-power needed 
to run the cryptography. There is a statement about these being less than 
device wake-up and sending messages, but some quantitative evaluation (in
percentage) of the impact would be useful, taking into account that battery 
capacity is one of the most important constrained resources.

Nits/editorial comments:

1. The document uses the alternate term of 'small devices' for 
'resource-constraint devices'. I view this as kind of an inaccurate verbal 
automatism in the world of IoT, as 'small' is a relative term, 
resource-constrained devices are not necessarily small (like in reduced 
physical footprint), and small devices can be rich in resources. I would 
suggest to either avoid the term, or explain what it means in the context (e.g.
''Smart objects', 'small devices' and 'resource-constrained devices are used 
interchangeably in this document and mean ...')

2. Please expand ECDSA at first occurrence

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