Re:Passive SSH Key Compromise via Lattices [pdf]
by SAI_Peregrinus on Monday November 06, 2023 @02:52PM
(#38167943)
I'd say encryption and PKCS#1v1.5. The latter is just hard enough to implement safely that it's quite likely to be vulnerable, but not so obviously bad as to be considered definitively broken & set for removal. PKCS#1v1.5 support might not be a deliberate backdoor, but allowing it in a new protocol today would be suspicious.
We went to curves largely due to the flaws of PKCS#1v1.5, not so much due to RSA itself being bad (though the false sense of simplicity it has is certainly dangerous). RSASSA-PSS verification is fast, so while the keys & signatures are big there's still some reason to use it for constrained devices.
It's just also the case that RSA in popular use is virtually never OAEP or PSS, and that this isn't a problem you have with ECC constructions, even if you're not using the most misuse-resistant of them.
It's also kind of a dead letter at this point. The ship has sailed: new designs all use curves, and have for something like a decade now.
(I didn't write a paper on this, but I do believe myself to be the proprietor of the Internet's single largest collection of Bleichenbacher padding oracle exploits, in every conceivable language, so there's my bona fides.)