I've been studying encryption on a hobby basis, and wanted to know if I got this basic cypher construction right (this is another experiment, see the AES ECB experiment thread earlier).


  1. XOR plain text block, initialization vector and counter together.
  2. AES resulting block.
  3. Increment counter.
  4. Goto 1 until all plain text blocks are done.

Authentication tag:

  1. Sha256 cipher text.
  2. AES resulting hash using authentication key.
  • $\begingroup$ As to the first part, this will answer your question: crypto.stackexchange.com/questions/14782/… $\endgroup$ – Richie Frame Mar 4 '15 at 20:21
  • $\begingroup$ For the second part, see crypto.stackexchange.com/questions/3229/… $\endgroup$ – Ilmari Karonen Mar 4 '15 at 21:03
  • $\begingroup$ Yeah, those posts explain it all. Thanks. It sure is easy to get this wrong. $\endgroup$ – Thorham Mar 5 '15 at 8:15
  • 1
    $\begingroup$ A common truth is: It is easy to design a scheme you can't break yourself. But it is an entirely different matter to design a scheme, which no one can break. $\endgroup$ – tylo Mar 5 '15 at 13:49

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