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Assert that MLKEM APIs generate real keys #470

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Assert that MLKEM APIs generate real keys #470

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@kornelski kornelski commented Feb 10, 2026 •
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It's scary that the MLKEM768_generate_key is a void function without ability to report an error. This adds a check that some seed/secret parseable public key has actually been written.

bwesterb
bwesterb reviewed Feb 10, 2026
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bwesterb reviewed Feb 10, 2026
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bwesterb commented Feb 10, 2026 •
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Why is it scary?

@kornelski kornelski mentioned this pull request Feb 10, 2026
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Timing side channel

@kornelski kornelski requested a review from bwesterb February 10, 2026 22:40
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bwesterb commented Feb 10, 2026

Still not safe.

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bwesterb commented Feb 10, 2026

We really shouldn't write this needless code. It's only more chances to get things wrong.

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kornelski commented Feb 10, 2026

ok, fine. I've removed the check for all-0 keys. Now it's just a good'ol error handling bugfix.

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kornelski commented Feb 10, 2026

BTW, why using CRYPTO_memcmp for comparison still wasn't safe?

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bwesterb commented Feb 10, 2026

CRYPTO_memcmp is safe. I read too quickly and thought you were calling this.

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