title: How to concatenate 3 NSData variables
body: <p>How to concatenate 3 <code>NSData</code> variables ?</p>
  
  <pre><code>NSData *iv;
  NSData *salt;
  NSData *encryptedData;
  </code></pre>
  
  <p>I need to join these to a single variable. Can any one show me a way.</p>