A shielding structure for a control module installed on the surface of a rear cover of a display comprises a plurality of engaging portions disposed at both lateral sides of the control module installed on the rear cover of the display, a shielding cover in which the control module can be accepted and a plurality of engaging sheets extended from the lateral sides of the shielding cover. The magnets form magnetic flux to be regularly generated and thus can generate uniform electromagnetic forces through interaction with current. A succession of variations are caused in the characteristic upstream of the exchanger, and a plurality of values of the characteristic upstream of the exchanger are continuously stored in memory. If the service connection request is accepted, the mobile device operates to establish and maintain, via the GAN, a service connection with the core network of the home PLMN for communications. The present invention provides data recovery from both a first number of data block failures due to random bit failures and a second number of storage unit failures while providing update write performance equivalent to data protection mechanisms with lower data recovery capabilities. In one form, the method of enabling functions includes detecting whether to install a custom install routine within a module configured to enable access to a hash function, and accessing a lock bit configured to lock access to the hash function.