showerthought:

in systems based on cryptography, is robustness under non-perfect execution more important than security under perfect execution?

I've just encountered this paper that shows a weakness in a certain mixnet design that can lead to full failure (decryption or even private key loss) based on guessing bits of an RSA ciphertext:

www-users.cse.umn.edu/~hoppern

That needs a ton of context (e.g. RSA does not have semantic security; this attack is particularly practical), (1/n)

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... but it's an illustration of the general feeling one gets from studying RSA application in the real world - see Bleichenbacher - it's *fragile*.

There is a similar story with Schnorr family signatures and nonces - correctly generated nonces are secure; but even *1* bit of bias can result in insecurity (again, practicality aside - so often, the impractical has the rude habit of becoming practical, once something is under wide use).

eprint.iacr.org/2019/023.pdf

eprint.iacr.org/2020/615.pdf

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edit: "this attack is *not* particularly practical" is what i meant to say in the first message, of course :)

@waxwing some of those kind of attacks are btw *practical* in the physical or sidechannel and timing attack schemes.

Using keys can reveal a lot of Information and in a digital world it is almost not preventable that someone hears the key bits *sound*.
So in my view keys should only be used once and not and never be deterministic derivable from *master* keys, i guess i am alone in that view ... , should i mention that i hate HD wallets, and that i refuse to use them?

thesun.co.uk/tech/12462646/bre

@waxwing i wonder how long it will take until the vaccination passport signer keys are revealed by that kind of attacks on the verifying apps.

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