title: boto encryption key with amazon s3
body: <p>As I see there with the function calls <code>set_contents_with_filename</code> or <code>set_contents_with_file</code>, I can set encryption to true and while in s3, it stays encrypted</p>
  
  <p>I have some questions </p>
  
  <ol>
  <li><p>If possible, I want to know, which is the key that is being used to encrypt the file. </p></li>
  <li><p>If encryption is set to true, the encryption takes place in server side right ? </p></li>
  <li><p>If encrypted, while downloading, the objects are decrypted in s3 and then start to download? Or does the decryption happen while downloading?</p></li>
  </ol>