Privacy Enhanced Fast Mutual Authentication in 5G Network Using Identity Based Encryption

Subscription privacy of a user has been a historical concern with all the previous generation mobile networks, namely, GSM, UMTS, and LTE. While a little improvement have been achieved in securing the privacy of the long-term identity of a subscriber, the so called IMSI catchers are still in existence even in the LTE and advanced LTE networks. Proposals have been published to tackle this problem in 5G based on pseudonyms, and different public-key technologies. This paper looks into the problem of concealing long-term identity of a subscriber and presents a protocol based on identity based encryption (IBE) to tackle it. The proposed solution can be extended to a mutual authentication and key agreement protocol between a serving network (SN) and a user equipment (UE). We name the protocol PEFMA (privacy enhanced fast mutual authentication). The SN does not need to connect with the home network (HN) on every PEFMA run. In PEFMA, both the user equipment (UE) and the SN has public keys. A UE sends the IMSI after encrypting it using the SN’s public key. Since both the UE and SN have public keys, PEFMA can run without contacting the HN. A qualitative comparison of different techniques show that our solution is competitive for securing the long-term identity privacy of a user in the 5G network.Peer reviewe

Experimental Analysis of Subscribers' Privacy Exposure by LTE Paging

Over the last years, considerable attention has been given to the privacy of individuals in wireless environments. Although significantly improved over the previous generations of mobile networks, LTE still exposes vulnerabilities that attackers can exploit. This might be the case of paging messages, wake-up notifications that target specific subscribers, and that are broadcasted in clear over the radio interface. If they are not properly implemented, paging messages can expose the identity of subscribers and furthermore provide information about their location. It is therefore important that mobile network operators comply with the recommendations and implement the appropriate mechanisms to mitigate attacks. In this paper, we verify by experiment that paging messages can be captured and decoded by using minimal technical skills and publicly available tools. Moreover, we present a general experimental method to test privacy exposure by LTE paging messages, and we conduct a case study on three different LTE mobile operators

Privacy-Preserving Access for Multi-Access Edge Computing (MEC) Applications

Multi-Access Edge Computing (MEC) is one of the emerging key technologies in Fifth Generation (5G) Mobile Networks, providing reduced end-to-end latency for applications and reduced load in the transport network. This paper is about user privacy in MEC within 5G. We consider a basic MEC usage scenario, where the user accesses an application hosted in the MEC platform via the radio access network of the Mobile Network Operator (MNO). First, we create a system model based on this scenario, then define the adversary model and privacy requirements for this system model. Second, we introduce a privacy-preserving access solution for the system model and analyze the solution against the privacy requirements.Peer reviewe

Providing Identity Privacy in 5G Networks by Using Pseudonyms

This thesis aims for presenting a solution for providing the identity privacy in mobile networks. The user is identified in mobile networks by an International Mobile Subscriber Identity (IMSI). An IMSI catcher is a device that acts like a fake base station and targets information such as identity and location. Location tracking is one of the most serious outcomes, in case attacker captures these details. Since building an IMSI catcher is now cheaper than before and detecting one is very hard, threat caused by this device has become a serious issue, especially while developing 5G. Several solutions to protect against IMSI catchers are explained in this thesis, and one solution for defeating IMSI catchers is using pseudonyms instead of real identity. We claim that pseudonym can be an effective solution for providing identity privacy in 5G networks and can be also compatible with legacy networks. We have implemented a prototype that demonstrates how pseudonym can be imposed to an existing Authentication and Key Agreement (AKA) procedure. This prototype has been presented in two public demonstration sessions. This thesis includes the history of the mobile networks including 5G. The changes between generations of networks show the requirements for better infrastructure, and also for improved security. We have also examined the development of AKA, since AKA is one of the most important procedures to provide secure service to valid users. Moreover, our prototype is about enhancing AKA for adapting pseudonym approach. This thesis also mentions about a block cipher called KASUMI, which is used for encrypting and decrypting pseudonym during AKA in the prototype. Since KASUMI is designed specifically for 3GPP and cryptanalyses show it is still safe to use KASUMI, it was chosen to be used in the prototype. Keywords: 5G, mobile networks, pseudonym, identity privacy, authentication and key agreement, KASUMI

METODY ZAPEWNIENIA BEZPIECZEŃSTWA DANYCH W STANDARDACH MOBILNYCH

The analysis of mobile communication standards is carried out, the functional structure and interfaces of interaction between the structural elements of the cellular network are considered. To understand the principle of communication according to the GSM standard, a block diagram of a mobile switching center (MSC), base station equipment (BSS), control and service center (MCC), mobile stations (MS) is presented. The main algorithms for ensuring the confidentiality and security of mobile subscribers' data, in different types of standards, as well as the vulnerabilities of information flows are considered. In particular, the following dangerous types of attacks have been identified, to which mobile network subscribers are sensitive: sniffing; leakage of personal data; leakage of geolocation data; spoofing; remote capture of SIM-card, execution of arbitrary code (RCE); denial of service (DoS). It is established that the necessary function of the mobile network is the identification of subscribers, which is performed by IMSI, which is recorded in the SIM card of the subscriber and the HLR of the operator. To protect against spoofing, the network authenticates the subscriber before starting its service. In the case of subscriber identification, the subscriber and the network operator are protected from the effects of fraudulent access. In addition, the user must be protected from eavesdropping. This is achieved by encrypting the data transmitted over the radio interface. Thus, user authentication in UMTS, as well as in the GSM network, is carried out using encryption with a common key using the "hack-response" protocol (the authenticating party sends a random number to the authenticated party, which encrypts it according to a certain algorithm using a common key and returns the result back).Przeprowadzana jest analiza standardów komunikacji mobilnej, rozważana jest struktura funkcjonalna i interfejsy interakcji między elementami strukturalnymi sieci komórkowej. Aby zrozumieć zasadę komunikacji w standardzie GSM, przedstawiono schemat blokowy centrali ruchomej (MSC), wyposażenia stacji bazowej (BSS), centrum sterowania i obsługi (MCC), stacji ruchomych (MS). Rozważane są główne algorytmy zapewniające poufność i bezpieczeństwo danych abonentów telefonii komórkowej, w różnych typach standardów, a także podatności na przepływ informacji. W szczególności zidentyfikowano następujące niebezpieczne rodzaje ataków, na które podatni są abonenci sieci komórkowych: sniffing; wyciek danych osobowych; wyciek danych geolokalizacyjnych; podszywanie się; zdalne przechwytywanie karty SIM, wykonanie dowolnego kodu (RCE); odmowa usługi (DoS). Ustalono, że niezbędną funkcją sieci komórkowej jest identyfikacja abonentów, która jest realizowana przez IMSI, która jest zapisywana na karcie SIM abonenta i HLR operatora. Aby zabezpieczyć się przed podszywaniem się, sieć uwierzytelnia subskrybenta przed uruchomieniem usługi. W przypadku identyfikacji abonenta, abonent i operator sieci są chronieni przed skutkami nieuprawnionego dostępu. Ponadto użytkownik musi być chroniony przed podsłuchem. Osiąga się to poprzez szyfrowanie danych przesyłanych przez interfejs radiowy. Tak więc uwierzytelnianie użytkownika w UMTS, jak również w sieci GSM, odbywa się z wykorzystaniem szyfrowania wspólnym kluczem z wykorzystaniem protokołu „hack-response” (strona uwierzytelniająca wysyła do strony uwierzytelnianej losową liczbę, która ją szyfruje zgodnie z pewien algorytm używający wspólnego klucza i zwraca wynik z powrotem)

A Survey of Subscription Privacy on the 5G Radio Interface - The Past, Present and Future

End-user privacy in mobile telephony systems is nowadays of great interest because of the envisaged hyper-connectivity and the potential of the unprecedented services (virtual reality, machine-type communication, vehicle-to-everything, IoT, etc.) being offered by the new 5G system. This paper reviews the state of subscription privacy in 5G systems. As the work on 5G Release 15 -- the first full set of 5G standards -- has recently been completed, this seems to be an appropriate occasion for such a review. The scope of the privacy study undertaken is limited to the wireless part of the 5G system which occurs between the service provider\u27s base station and the subscriber\u27s mobile phone. Although 5G offers better privacy guarantees than its predecessors, this work highlights that there still remain significant issues which need rectifying. We undertook an endeavor to (i) compile the privacy vulnerabilities that already existed in the previous mobile telephony generations. Thereafter, (ii) the privacy improvements offered by the recently finalized 5G standard were aggregated. Consequently, (iii) we were able to highlight privacy issues from previous generations that remain unresolved in 5G Release 15. For completeness, (iv) we also explore new privacy attacks which surfaced after the publication of the 5G standard. To address the identified privacy gaps, we also present future research directions in the form of proposed improvements