A temporary-identity-storage method for user equipment includes receiving authentication challenge information and at least one temporary identity, processing the authentication challenge information, and determining whether the processing step results in successful authentication. The user equipment includes mobile equipment and a subscriber identity module. Responsive to a determination that the authentication was successful, the received at least one temporary identity is considered to be valid. If the received at least one temporary identity is at least one pseudonym and an appropriate data file to the store the at least one pseudonym is available in the subscriber identity module, the at least one pseudonym is stored and any previously-stored pseudonym is over-written in the subscriber identity module. If the received at least one temporary identity is at least one pseudonym and an appropriate data file to the store the at least one pseudonym is not available in the subscriber identity module, the at least one pseudonym is stored and any previously-stored pseudonym is over-written in the mobile equipment. This Abstract is provided to comply with rules requiring an Abstract that allows a searcher or other reader to quickly ascertain subject matter of the technical disclosure. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).