2 2 2The first five to six digits of the IMSI identify the country and the home network of the mobile user. A pseudonym looks like a normal IMSI, but its last nine to ten digits are randomized and frequently changing. We take a similar approach as proposed in these papers. IMSI catchers in mobile networks has been studied in several works during the recent years. The idea of using pseudonyms in IMSI format to confound Our solution uses pseudonyms that have the same format as IMSI for LTE communication to defeat the downgrade attack. User equipment and home network in order to provide identity privacy.Īdditionally, lawful interception requires minor patching in the serving Our mechanisms utilizeĮxisting LTE and 3GPP Release 15 messages and require modifications only in the Synchronized when the user equipment connects to 5G. Pseudonyms in the user equipment and home network are automatically The latter helps to recoverįrom a loss of synchronization of LTE pseudonyms. Protect user identity privacy of 5G user equipment against IMSI catchers in LTEĪnd (ii) to include a mechanism for updating LTE pseudonyms in the public keyĮncryption based 5G identity privacy procedure. We propose (i) to use an existing pseudonym-based solution to

Privacy, where a fake LTE base station obtains the identity of a 5G userĮquipment. Networks which opens the possibility of a downgrade attack on user identity Despite this protection, IMSI catching is still possible in LTE These protection mechanisms are based on public 3GPP Release 15, the first 5G standard, includes protection of user identity

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