UniqueIdentifier in ios 7

Before deprecation of uniqueIdentifier it was good to use same identifier even deleting app and even erasing iPhone. After that I use MAC address and that was also working before iOS 7, but with iOS 7 it gives 2c:00:00:00:00:00. So I am not getting any way to get unique identifier. If is use IdentifierForVender: it gives different identifier if I delete the all the app of same vendor.

MAC Address : it works fine but not on iOS 7.

UniqueIdentifier :deprecated.

Please tell me the way to get unique value even app deletion and even erasing iPhone(like factory restore)