title: objective C iOS Device ID in iOS7
body: <p>I want to ask that whether objective C can obtain a unique device ID of the Device. "uniqueIdentifier" is deprecated in iOS7 and I try to use "identifierForVendor" but it gives me a different ID after the app is re-installed. I want to find a stable device ID after the app is re-install, and even the iOS is changed. In the early version of iOS, we can use MAC address to achieve such goal. But now, in iOS7, the MAC address is no longer available. How can i find a stable device ID of the iOS device in iOS7?</p>
  
  <p>Maybe using Keychain to store the "identifierForVendor" value is a good approach. But will it still be the same after the whole iOS is re-installed?</p>