Subject: Re: [Suit] Manifest Formats

From: Brendan Moran <[email-masked]>
Date: Mon, 4 Dec 2017 20:11:15 +0000

> On 29 Nov 2017, at 04:58, Cullen Jennings <[email-masked]> wrote:
>
>
>> On Nov 23, 2017, at 9:13 AM, Hannes Tschofenig <[email-masked]> wrote:
>>
>> Hi Suhas,
>>
>>
>>
>> The way we would like this to work is not to have the update server create these manifests in real-time, based on what the device asks for. Instead, the manifests are created and signed by the developer (using a tool or a web service). The update server is mainly a repository. This approach provides better security.
>>
>>
>
> How would that work? Would the update server, an online computer on the internet, need have the private key to sign the manifests? I can assure you that many IoT vendors do not handle their software signing keys that way.
>
> I imagine this working that a given vendor would likely only use one format but an update server could serve up manifests in any format. Sure one format would be nice but no matter which one you choose, a bunch of vendors will not like it and will do something else. The important part is the deciding the semantic level information and design choices. The syntax is really not the hard part of any of this yet different vendors have strong opinions about this often with very good reasons.

The expectation in draft-moran-suit-manifest00 is that end-to-end security is used, and all online repositories are inherently distrusted.

The argument is that the author of an update will know which serialisation is expected by the recipient device. I think that it is more complex than this, however, so I believe that it is best to support a single canonical representation.

Best Regards,
Brendan
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