title: Python XOR Decryption Only Decrypting Half of RGB Image
body: <p>I am trying to XOR decrypt an encrypted image in Python using a provided key. 
  I have been able to decrypt half of the image, and I can't understand why the bottom half does not get decrypted as well.</p>
  
  <pre><code>key = np.load('key.npy')
  secret = plt.imread('secret.bmp')
  
  newArr = secret.copy()
  
  for t, k in zip(secret, key):
      e = t^k
      newArr[t] = e
  
  plt.imshow(newArr)
  </code></pre>
  
  <p>Is there something wrong with my loop that makes the decryption stop after only traversing half the image rows?</p>
  
  <p><a href="https://i.stack.imgur.com/BcAuf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BcAuf.png" alt="enter image description here"></a></p>