Given an AES key that is wrapped using another AES key, the second one being generated using PBKDF2, and given that I know the wrapped key: can I derive the passphrase that went into the PBKDF2? (asking for a friend)

  • $\begingroup$ this could be about the key wrapping, rather than about PBKDF2 itself. please correct me if the question is wrong. $\endgroup$ – rmalchow Feb 9 at 11:38
  • $\begingroup$ also, i AM using a salt. $\endgroup$ – rmalchow Feb 9 at 11:38
  • $\begingroup$ whoever downvoted this question - it would be nice to know what i did wrong (so i can avoid it next time) $\endgroup$ – rmalchow Feb 9 at 12:07
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    $\begingroup$ PBKDF2 is so obviously non-reversible that your friend shouldn't even be bothering you to ask it for him. This question is therefore showing no effort from either you or your friend. $\endgroup$ – DannyNiu Feb 9 at 12:10

PBKDF2 is not reversible using any semi-safe underlying hash function, including for instance SHA1 or even MD5.

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  • $\begingroup$ How can you affirm such? Are you an NSA-operative? $\endgroup$ – super Feb 11 at 19:44
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    $\begingroup$ How can you affirm anything? Maybe P=NP? I am confident there are no publicly known methods to find a PBKDF2 preimage. I would be shocked if the nsa can(They may have dedicated hardware with a speedup of a few order of magnitudes, but that is not it). $\endgroup$ – Meir Maor Feb 12 at 5:36

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