p>The ECB mode should <em>never</em> be used.</p>
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<p>In particular, it is <em>not</em> <a href="../../Security%20Definitions/Chosen%20Plaintext%20Attack%20(CPA).html">CPA-secure</a>, since it is entirely deterministic. Moreover, it is not even <a href="../../Security%20Definitions/Ciphertext-Only%20Attack%20(COA)/Semantic%20Security.html">semantically secure</a> because if a block is repeated in the plaintext, then the corresponding ciphertext block will also be repeated in the ciphertext whic