Improving Air Interface User Privacy in Mobile Telephony

Although the security properties of 3G and 4G mobile networks have significantly improved by comparison with 2G (GSM), significant shortcomings remain with respect to user privacy. A number of possible modifications to 2G, 3G and 4G protocols have been proposed designed to provide greater user privacy; however, they all require significant modifications to existing deployed infrastructures, which are almost certainly impractical to achieve in practice. In this article we propose an approach which does not require any changes to the existing deployed network infrastructures or mobile devices, but offers improved user identity protection over the air interface. The proposed scheme makes use of multiple IMSIs for an individual USIM to offer a degree of pseudonymity for a user. The only changes required are to the operation of the authentication centre in the home network and to the USIM, and the scheme could be deployed immediately since it is completely transparent to the existing mobile telephony infrastructure. We present two different approaches to the use and management of multiple IMSIs

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

The SUCI-AKA Authentication Protocol for 5G Systems

Security is a fundamental requirement for all digital systems. In this paper we propose a new entity authentication protocol, which we call the SUCI-AKA protocol. In contrast to the existing 5G-AKA protocol, it will provide online mutual entity authentication. A central design criteria has been to provide a solution which minimizes the system impact and avoids hard breaks with existing schemes. The SUCI-AKA protocol is largely based on the new 5G scheme for subscriber privacy, and integrates it with the existing 5G-AKA entity authentication protocol in a novel way. This provides scope for accommodating both credible subscriber privacy and online mutual entity authentication

On the security of an anonymous roaming protocol in UMTS mobile networks

In this communication, we first show that the privacy-preserving roaming protocol recently proposed for mobile networks cannot achieve the claimed security level. Then we suggest an improved protocol to remedy its security problems