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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)

rmalchow
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  • this could be about the key wrapping, rather than about PBKDF2 itself. please correct me if the question is wrong. – rmalchow Feb 09 '20 at 11:38
  • also, i AM using a salt. – rmalchow Feb 09 '20 at 11:38
  • whoever downvoted this question - it would be nice to know what i did wrong (so i can avoid it next time) – rmalchow Feb 09 '20 at 12:07
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    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. – DannyNiu Feb 09 '20 at 12:10

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

Meir Maor
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  • How can you affirm such? Are you an NSA-operative? – super Feb 11 '20 at 19:44
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    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). – Meir Maor Feb 12 '20 at 05:36