title: Encrypting unicode strings with pyaes
body: <p>The following code works well:</p>
  
  <pre><code>import os, pyaes
  key = os.urandom (16)
  aes = pyaes.AESModeOfOperationCTR (key)
  encrypted = aes.encrypt ('Hello world')
  aes = pyaes.AESModeOfOperationCTR (key)
  decrypted = aes.decrypt (encrypted)
  print (encrypted)
  print (decrypted)
  </code></pre>
  
  <p>But when I try to encode a unicode string, like a string containing hebrew letters for example, it raises an error:</p>
  
  <pre><code>ValueError: bytes must be in range(0, 256)
  </code></pre>
  
  <p>How can I encode unicode characters?</p>