I got two audio files one is encrypted and the other file is a part of the plaintext. I want to extract all the plaintext. I am using the AES-ECB mode, the size of the block is 128 bits and the start of the extracted plaintext is not aligned with the start of the cipher text. So I need to align these two audio files. I don't know how to do that and how that would help me to extract all the plaintext.

  • $\begingroup$ Welcome to Cryptography.se What is the origin of this problem? $\endgroup$
    – kelalaka
    Oct 22 at 19:45
  • $\begingroup$ it is a homework . I need to write a python code to solve it.I wasn't able to figure out the idea. I understand the weakness of AES-ECB mode but I don't know how can i exploit that in this problem. $\endgroup$ Oct 22 at 19:47
  • $\begingroup$ A small hint as per our policy: One possible way is to find two ciphertext blocks that are the same and at the same time, you had the same in the plaintexts. $\endgroup$
    – kelalaka
    Oct 22 at 19:49
  • $\begingroup$ okay thank you for the hint. I will try to work on that. $\endgroup$ Oct 22 at 19:57
  • $\begingroup$ Keeping in consideration that my two audio files are not aligned, i tried to search for the repetaed blocks in the encrypted file and in the plaintext file. I extracted the pattern for each block; how many each block is repeated and in what indexes. I tried to make a match but i didn't find any. Could you tell me if i am in the right path or i should look for another alternative? $\endgroup$ Oct 22 at 21:41


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