A method for obtaining authentication credentials for attaching a wireless device to a foreign wireless domain in a 3rd Generation Partnership Project (3GPP) communication system, which includes: receiving an attach request message from the wireless device; and responsive to the attach request message, authenticating the wireless device and retrieving a set of authentication vectors, wherein the authentication vectors are for authenticating the wireless device to the foreign wireless domain. The method further includes encrypting the set of authentication vectors using a first security key of a home wireless domain of the wireless device. In addition, the method includes encrypting the first security key using a second security key of the foreign wireless domain and sending the encrypted set of authentication vectors and the encrypted first security key to the wireless device.