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A comment on PSA: Upgrade your LUKS key derivation function. Parent comment

Re:PSA: Upgrade your LUKS key derivation function by aborsy on Tuesday April 18, 2023 @07:42AM (#35612660)
You don’t need to merely tend towards. You just can’t brute force a random 20 characters password of the type that he mentioned. Brute force is almost never used, even with half of entropy of such password.

His password was intercepted, or was embarrassingly deterministic.

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Re:PSA: Upgrade your LUKS key derivation function by raverbashing on Tuesday April 18, 2023 @08:23AM (#35613031)
Or something like, notebook still had the keys in memory when it was recovered

Though from this description it looks like they read the disk (trivial) but it's not sure if they actually pulled anything from it (at least it seems they didn't pull anything incriminating if I read it correctly).

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Re:PSA: Upgrade your LUKS key derivation function by mort96 on Tuesday April 18, 2023 @10:49AM (#35614742)
I didn't see anyone mention a random 20 characters password. I saw 20 character password with symbols and upper and lower case. That might be 4 words strung together "correct horse battery staple" style.
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Re:PSA: Upgrade your LUKS key derivation function by mjg59 on Tuesday April 18, 2023 @02:45PM (#35618166)
A stronger KDF would plausibly have protected him even if his password was embarrassingly deterministic.
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Re:PSA: Upgrade your LUKS key derivation function by stouset on Tuesday April 18, 2023 @05:48PM (#35620785)
Maybe. But probably not.

If they were using a crib sheet to the point of only trying 1m attempts, this can be done in “days” with one CPU even if PBKDF2 is set to take one second each attempt on that CPU.

A “better” KDF isn’t fundamentally going to change this. It’s just going to enforce stricter limits on any time-memory trade offs and require more memory. Neither of these are going to be meaningful differences when you’re cracking a single password for a single user with a crib sheet, unless you’re in the realm of billions or more guesses.

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