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Re: [Cbor] Packed CBOR review

Christian Amsüss <christian@amsuess.com> Fri, 18 June 2021 08:05 UTC

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Date: Fri, 18 Jun 2021 10:05:47 +0200
From: Christian Amsüss <christian@amsuess.com>
To: Brendan Moran <Brendan.Moran@arm.com>
Cc: Carsten Bormann <cabo@tzi.org>, "cbor@ietf.org" <cbor@ietf.org>
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Subject: Re: [Cbor] Packed CBOR review
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On Thu, Jun 17, 2021 at 11:17:34AM +0000, Brendan Moran wrote:
> > How would the hash reference specify the algorithm?
> > (I think CFRG would tell us that collision resistance between algorithms isn’t a well-defined property.)
> 
> We could possibly reuse SUIT digest definitions for this:
> suit-digest = [algorithm-id : uint, digest: bstr]

When we already cater for URIs, we could just use RFC6920 URIs that do
express the used hash -- example:
ni:///sha-256;UyaQV-Ev4rdLoHyJJWCi11OHfrYv9E1aGQAlMO2X_-Q

That's annoying encoding and verbose, but CRIs could maybe (ok, it's a
big maybe) provide a compact serialization for them if [#5] happens.

BR
c

[#5]: https://github.com/core-wg/coral/issues/5

-- 
To use raw power is to make yourself infinitely vulnerable to greater powers.
  -- Bene Gesserit axiom

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