I largely agree with this, but just wanted to mention that what matters is the 
lifetime of the keys not the lifetime of the tokens. Of course, short-lived 
tokens mean you can typically rotate your keys frequently too, but that’s not 
always possible eg for keys embedded in hardware.

> On 17 Oct 2025, at 20:41, Simo Sorce <[email protected]> wrote:
> 
> Lucas,
> while LAMPS may have different needs, I do not understand what
> composites
> bring to JOSE or COSE, the JWT and JWS tokens are generally short-lived
> entities, therefore there is no need for long term protection against
> CRQC.
> 
> And for short term protection there is no point in dual signatures, if
> a CRQC is available the classic part is irrelevant. And until a CRQC is
> available the QR part is redundant.
> 
> I think this will just add complexity with no value, complexity means
> more bugs and more ways to screw up, and must always be justified.
> 
> Additionally, in terms of timing:
> 
> - If a CRQC is expected soon all this work is net overhead for
> basically no gain as classic signatures will be obsolete quickly, and
> going though composite signatures will cause dual migrations classic ->
> composite -> pureQR, which is operationally expensive and doubles the
> pain.
> 
> - If a CRQC is not expected soon, then rushing into composites is also
> not useful, it is better to stay on a classic signature until the time
> pureQR are trustworthy enough to do the migration once.
> 
> Note that for a PKI infrastructure that provides CA certificates that
> have a long life the considerations may be quite different, so LAMPS
> has more reasons to entertain composite signatures at least for CA
> certificates.
> 
> Because I do not see a cryptographic relevant justification I am
> somewhat against adding composite signatures to JOSE (can't speak about
> COSE because I am not as familiar with its application space).
> 
> Simo.
> 
> On Fri, 2025-10-17 at 15:35 +0000, Lucas Prabel wrote:
>> 
>> 
>> Hi Orie, thanks for your feedback.
>>  
>> I think the point about the specific use cases is not specific to hybrid 
>> composite signatures, but could also be raised for pure PQ signatures, which 
>> didn’t prevent the COSE ML-DSA draft to be adopted by the COSE WG.
>>  
>> The LAMPS composite draft has already been adopted and is in WGLC. Given the 
>> 2030 migration timelines announced by several security agencies and 
>> organizations, I also believe waiting too long to standardize such 
>> mechanisms could make it difficult for some systems to achieve compliance in 
>> time.
>>  
>> Best,
>>  
>> Lucas
>>  
> 
> -- 
> Simo Sorce
> Distinguished Engineer
> RHEL Crypto Team
> Red Hat, Inc
> 
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