title: How to detect a cracked iPhone App and a jailbroken device (different methods)
body: <p>I'm building a blacklisting service for cracked iPhone apps and I am curious if I missed a method for detecting cracked apps.</p>
  
  <p>In the moment following app crack detection methods are available for the service:</p>
  
  <ol>
  <li>checking <strong>plist size</strong></li>
  <li>checking <strong>signer identity</strong></li>
  <li>checking if binary is <strong>crypted</strong> (not sure if this is working correctly since no cracked app got detected this way)</li>
  <li>checking <strong>modified date</strong> of info.plist against modified date of package (not sure if this is working - used code like: <a href="http://snippie.net/snip/f7530ff2" rel="noreferrer">http://snippie.net/snip/f7530ff2</a> to do that)</li>
  </ol>
  
  <p>I also wonder if it is possible to check if the device is jailbroken? 
  This would help, too, because the service will work much like a spam blacklist and jailbreak could be used to increase the score.</p>
  
  <p>I have also included a honeypot, which shows me that the tools used by the crackers eliminate some of the checks I do.  For instance the plist check for size or signer identity.</p>
  
  <p>My question is now: </p>
  
  <ul>
  <li><strong>Are there more "good" checks I should use?</strong></li>
  </ul>
  
  <p>and </p>
  
  <ul>
  <li><strong>Is there a way to detect Jailbreak?</strong></li>
  </ul>
  
  <p>Thanks for any help!</p>