Good morning,

On Fri, February 2, 2024 3:05 am, Lijun Liao wrote:
> 1. oid: It is fine for me to extend it by only the PEN option.
> 2. signatureAlgorithm: the only reason I see here is it breaks the already
> deployed certificates.

The only reason to make this breaking change at this point in time is if
there is a consensus that one-pass processing of signatures is an absolute
requirement.  I, for one, do not see that need.  I work in very small
environments, and I have not seen that need, yet.

>   2.1. Considering the PQC certificate, the public key may be several
> kilo-bytes, without the one-pass signature property, the additional
> required memory usage is not ignorable.

Okay, let's look at the NIST PQC algorithms:

A Dilithum public key is 1-1.5 KB and signature is about 2-3 KB. (total
3-4.5 KB)
A Falcon public key is 1-2 KB and signature is about 1 KB. (total 2-3 KB)

Yes, this is much larger than the 32-64B of ECC, but in the grand scheme
of things, compared to pretty much any other data structure, this
additional size *IS* ignorable.

If we were talking multiple tens of KBs, let alone MBs, then I would agree
with you that we should revisit the topic.  But even the smallest of
devices can easily hold 2-5KB of data in RAM.

>  2.2. As mentioned in the
> https://github.com/cose-wg/CBOR-certificates/issues/152,  if the CRL have
> the same structure as in the current certificate, the impact may be much
> larger. To parse the CRL, the application has to parse the
> *revokedCertificates* field before getting the signature algorithm. And
> since revokedCertificates may be very large, e,g. In mega-bytes. IMHO,
> putting the *signatureAlgorithm* at the begging is necessary.
> 2.3. To unify the structures of certificates and CRLs, I think
> *signatureAlgorithm* shall also be at the begging. To keep the backwards
> compatibility with the deployed certificates, we shall increase the syntax
> version (the *version* field).

I see no requirement or need to have the Certificate and CRL share a
structure format.  From where is that requirement stemming?

Thanks,

-derek

-- 
       Derek Atkins                 617-623-3745
       [email protected]             www.ihtfp.com
       Computer and Internet Security Consultant

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