Assume I have a plaintext and a ciphertext, encrypted using some key and AES with CBC mode. I don't have a service, that I can send something to, so I can't use the Padding Oracle attack. Are there any ways to get the key? I also know that the message was encrypted twice using random words from a very big dictionary.

  • $\begingroup$ Do you know how the AES key(s) are obtained from "random words from a very big dictionary" ? That's critical. Also, "encrypted twice" is ambiguous; is it that the same message was encrypted twice and you get two ciphertexts, or the ciphertext from the first encryption was re-encrypted and you get only the second ciphertext? $\endgroup$
    – fgrieu
    Dec 11, 2020 at 16:04
  • $\begingroup$ @fgrieu The words are obtained by using choice from secrets python library. Encrypted twice in this case means that the plaintext was encrypted by one key and then again by another $\endgroup$
    – Anegng
    Dec 11, 2020 at 16:59
  • $\begingroup$ Is this some CTF? $\endgroup$
    – kelalaka
    Dec 11, 2020 at 18:09
  • $\begingroup$ No, I am just training, I found this problem interesting, but could not solve it $\endgroup$
    – Anegng
    Dec 11, 2020 at 19:32


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