# Tweet by [@keefmoon](http://twitter.com/keefmoon) on 2012-03-24 08:19:55 > [!INFO] Archived from [original tweet](http://twitter.com/keefmoon/status/183468169862717441) RT @steipete: iPhone's UDID is itself calculated, not fixed itself. UDID = SHA1(SerialNumber + IMEI + WiFiAddress + BluetoothAddress) ht ...