> I would like to register my strong objection to this working group promoting 
> the use of non-hybrid ML-KEM in any way, or any other non-hybrid
> post-quantum cryptosystem. 


I would like to register my strong disagreement with the above position. And 
register support for allowing the use of “pure”, aka non-hybrid ML-KEM (and 
other non-hybrid PQ cryptosystems).


Among the reasons — since the goal of PQC is protecting data with long-term 
value — protection given by the Classic part of the hybrid is meaningless 
against the threat of “Record Now, Decrypt Later”. Confidentiality of the 
recorded-now sensitive data relies solely on the PQ part of the hybrid.


The only use case when hybrid adds anything meaningful, is if your data value 
is short-lived, so it is not likely to be exposed to CRQC — so, Classic alone 
would suffice, and adding PQ KEM doesn’t hurt.


The only situation when hybrid could make sense for a "long-term” data is if:



1. Crypto-Relevant Quantum Computer does not materialize; and
2. PQ algorithm falls to a Classic attack; and
3. Classic algorithm remains unbroken.



> The correct course of action is to recommend against such an ill-advised 
> decision,


That’s a matter of opinion. I consider your recommendation ill-advised, for 
reasons stated above.


> The performance improvements of a non-hybrid approach are trifling;


Correct. Though this depends on the use case — some would welcome the speedup 
of Lattice-based crypto over ECC.
But this is not about the extra computations required for hybrid.


> the security risks are immense,


Simply not true. See above. The logic above is straightforward enough.


Also, this might be instructive:


System
Proposed
Standardized
Lag-to-Standardization
Math-Studied-For-How-Long
RSA
1977
~1993–1995
~15–20 years
Number theory: 2000+ years
ECC
1985
~1998–2000
~13–15 years
Elliptic curves: ~150 years
Lattice crypto
1996
2022–2024
~25 years
Lattices: ~150–200 years
McEliece 1978 2024 ~46 years Codes: ~60-75 years


> given the breadth of attempted post-quantum cryptosystems that have fallen to 
> classical attacks;


Given the number of standardized successful post-quantum crypto systems that 
stand strong, we shouldn’t panic needlessly.


> I am baffled that so many people are taking a stand in favor of a non-hybrid 
> system, which is transparently unwise.


Well, “wisdom" apparently is a relative term, because to me the position you’re 
advocating seems unwise.


> For context, cryptography is not my area of research


Coincidentally, it is mine. Plus, a few decades of experience (and some 
publications & patents, nothing earth-shattering).



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