Re: [core] OSCORE: Questions about Section 5.2

Jaro Fietz <jaro.fietz@aisec.fraunhofer.de> Thu, 11 October 2018 12:41 UTC

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From: Jaro Fietz <jaro.fietz@aisec.fraunhofer.de>
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Date: Thu, 11 Oct 2018 14:41:30 +0200
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Subject: Re: [core] OSCORE: Questions about Section 5.2
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Hello Christian,

thanks for your quick answer, it clarified the second of my questions.

On 10/11/18 1:09 PM, Christian Amsüss wrote:
> The expectation is that the shortest (zero-length) ID would be used in
> cases wherever that's beneficial, eg. when a constrained device
> primarily utilizes one context in which it is addressed as a server.
This is an interesting optimization. I'm not too sure about the actual 
benefits though. To me this would only result in the constrained nodes 
being able to shave off a few bytes of allocation when constructing the 
response and saving their sender_id to persistent storage.
> You briefly had me worried I got it wrong myself -- but the
> left-trimming that's happenign is on the sequence numbers, not on the
> sender IDs.
Sorry, I must have skipped incorrectly over the tuple construction. 
Reading through it again, your code is, of course, correct :)
> Slightly off topic: Would that happen to be a freely licensed
> implementation? If so, I know of an embedded operating system project
> that would love to hear about this.
I'm implementing OSCORE on top of zephyr (not integrated into it) for an 
embedded board. Currently it isn't open source, but I asked my advisor, 
who'll forward the request to the supervisor.
Judging from your github history I expect you ask for RIOT-OS? :)

BR,
Jaro