5 ms·

Compression does not introdoce entropy to a stream. Please refer to Shannon's source coding theorm. If anything, it reduces entropy.

• hackinthebochs 7y ago
  But it does increase the entropy per byte, thus making patterns harder to spot.
  • kop316 7y ago
    ....so your argument us to hope an adversary only sees part of your video and not all of it?
    • johncolanduoni 7y ago
      No, their argument is that if you have a higher entropy per byte, there will be more variation in the aligned 16-byte chunks that are relevant for attacking AES-128-ECB. This reduces the probability of the attacker being able to find equal blocks.
      • kop316 7y ago
        And my argument is if I know the video encoding and compression sequence, I wouldn't depend on AES-ECB. I know the patterns that show up. If I am encrypting something, I only want to depend on the strength of the encryption. I don't want to hope that something else ensures that an adversary cannot figure out my ciohertext. That is a very bad idea.
        • johncolanduoni 7y ago
          Sure, and nobody was arguing they should have used ECB or that they shouldn’t change it. Only that the ability to exploit this given compressed data is lower than the uncompressed penguin image example.