> But if I am honest, NIST recommending it at all is enough to suspect it of being compromised.

NIST isn't the NSA and doesn't have the NSA's goals in mind. They are briefed by NSA on some matters, sure, but they're not the same organization.

NSA has a dual mission: Both SIGINT and COMINT. While the SIGINT folks might rub their hands and laugh evilly at the prospect of backdooring the PQ KEM that the Internet wants to move towards, this plot makes no sense at several levels.

The NSA has, through CNSA 2.0, committed to moving the entire federal government onto ML-KEM for top secret communications. The COMINT guys would shit themselves in rage if it turned out to be backdoored, even if there was enough hubris that the backdoor was NOBUS.

If you can't trust the people, you should always seek to understand their incentives if you want to predict their behavior.

My interpretation of the CNSA 2.0 move was that the NSA believes 1) that ML-KEM is actually the good stuff, and 2) the Suite B transition failed so spectacularly that they want to signal confidence in ML-KEM by recommending it without hybridization. Since pretty much everything they do is top secret, they probably can't comment further.

In the past NSA has weakened encryption standards, for example NSA madified DES standard. The NSA pushed backdoored design of Dual_EC_DRBG was standardized in NIST SP 800-90A.

"Weaknesses in the cryptographic security of the algorithm were known and publicly criticised well before the algorithm became part of a formal standard endorsed by the ANSI, ISO, and formerly by the National Institute of Standards and Technology (NIST). One of the weaknesses publicly identified was the potential of the algorithm to harbour a cryptographic backdoor advantageous to those who know about it—the United States government's National Security Agency (NSA)—and no one else. In 2013, The New York Times reported that documents in their possession but never released to the public "appear to confirm" that the backdoor was real, and had been deliberately inserted by the NSA as part of its Bullrun decryption program."

https://en.wikipedia.org/wiki/Dual_EC_DRBG

"NSA worked closely with IBM to strengthen the algorithm against all except brute-force attacks and to strengthen substitution tables, called S-boxes. Conversely, NSA tried to convince IBM to reduce the length of the key from 64 to 48 bits. Ultimately they compromised on a 56-bit key"

https://en.wikipedia.org/wiki/Data_Encryption_Standard

The NSA published algorithms are not used for the important US secrets. For these system the classified algorithms of NSA Suite A are used.

https://en.wikipedia.org/wiki/NSA_Suite_A_Cryptography

NSA Suite A was probably used for Space Shuttle comunication. NASA scrambled to recover classified communications gear after the Challenger shuttle disaster in 1986.

https://www.globalsecurity.org/org/news/2003/030206-comsec-s...

You're argument is that I shouldn't think of NIST as a patsy for the NSA, is because the NSA can't possibly be recommending a compromised cipher, because if they were, that would mean this US government org is horribly defective and dysfunctional, where one side didn't know what the other was doing?

Incentives are basically all I consider when trying to establish true motive. But you're not required to consider motive when there's a history or pattern. Even if "It's the way we've always done it", wasn't a much, much stronger motive than thought/reason is for any human. It's both logical and desired to treat something as the most dangerous until proven otherwise.

I used to be a nurse. I remember when working in the ED, I was taught that every single woman on childbearing age who comes into the ED with abdominal pain is an extopic pregnancy until proven otherwise. If you ask a woman if it's possible she could be pregnant, regardless of the truth, many will claim it's impossible. If you blindly trust them, and delay treatment, you could needlessly kill your patient, or leave them infertile. Why would someone lie and risk that? Or how dare your medical team make assumptions like that? Well the alternative is worse, the reality should be easy to prove.

NIST has a history of recommending broken ciphers. That's not a mistake a professional would ever make. So thinking about incentives, I'm going to treat it like it was intentional. Here the group with a history for fucking up, isn't being transparent. I would love it if NIST would say enough to make DJB happy or at least stop pretending like they deserve any trust anymore.

Until then, I don't find "they're probably behaving like rational actors" compelling enough to trust them with keeping secrets from somebody who I actually do trust.