Shadow Phone and Ghost SIM: A Step Toward Geolocation Anonymous Calling

abstract: Mobile telephony is a critical aspect of our modern society: through telephone calls, it is possible to reach almost anyone around the globe. However, every mobile telephone call placed implicitly leaks the user's location to the telephony service provider (TSP). This privacy leakage is due to the fundamental nature of mobile telephony calls that must connect to a local base station to receive service and place calls. Thus, the TSP can track the physical location of the user for every call that they place. While the The Internet is similar in this regard, privacy-preserving technologies such as Tor allow users to connect to websites anonymously (without revealing to their ISP the site that they are visiting). In this thesis, the scheme presented, called shadow calling, to allow geolocation anonymous calling from legacy mobile devices. In this way, the call is placed from the same number, however, the TSP will not know the user's physical location. The scheme does not require any change on the network side and can be used on current mobile networks. The scheme implemented is for the GSM (commonly referred to as 2G) network, as it is the most widely used mode of mobile telephony communication. The feasibility of our scheme is demonstrated through the prototype. Shadow calling, which renders the users geolocation anonymous, will be beneficial for users such as journalists, human rights activists in hostile nations, or other privacy-demanding users.Dissertation/ThesisMasters Thesis Computer Science 201

SECURITY AND PRIVACY ISSUES IN MOBILE NETWORKS, DIFFICULTIES AND SOLUTIONS

Mobile communication is playing a vital role in the daily life for the last two decades; in turn its fields gained the research attention, which led to the introduction of new technologies, services and applications. These new added facilities aimed to ease the connectivity and reachability; on the other hand, many security and privacy concerns were not taken into consideration. This opened the door for the malicious activities to threaten the deployed systems and caused vulnerabilities for users, translated in the loss of valuable data and major privacy invasions. Recently, many attempts have been carried out to handle these concerns, such as improving systems’ security and implementing different privacy enhancing mechanisms. This research addresses these problems and provides a mean to preserve privacy in particular. In this research, a detailed description and analysis of the current security and privacy situation in the deployed systems is given. As a result, the existing shortages within these systems are pointed out, to be mitigated in development. Finally a privacy preserving prototype model is proposed. This research has been conducted as an extensive literature review about the most relevant references and researches in the field, using the descriptive and evaluative research methodologies. The main security models, parameters, modules and protocols are presented, also a detailed description of privacy and its related arguments, dimensions and factors is given. The findings include that mobile networks’ security along with users are vulnerable due to the weaknesses of the key exchange procedures, the difficulties that face possession, repudiation, standardization, compatibility drawbacks and lack of configurability. It also includes the need to implement new mechanisms to protect security and preserve privacy, which include public key cryptography, HIP servers, IPSec, TLS, NAT and DTLS-SRTP. Last but not least, it shows that privacy is not absolute and it has many conflicts, also privacy requires sophisticated systems, which increase the load and cost of the system.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Privacy through Pseudonymity in Mobile Telephony Systems

Abstract—To protect mobile phone from tracking by third parties, mobile telephony systems rely on periodically changing pseudonyms. We experimentally and formally analyse the mechanism adopted to update these pseudonyms and point out design and implementation weaknesses that defeat its purpose by allowing the identification and/or tracking of mobile telephony users. In particular, the experiments show that the pseudonym changing mechanism as implemented by real networks does not achieve the intended privacy goals. Moreover, we found out that the standard is flawed and that it is possible to exploit the procedure used to assign a new pseudonym, the TMSI reallocation procedure, in order to track users. We propose countermeasures to tackle the exposed vulnerabilities and formally prove that the 3GPP standard should require the establishment of a fresh ciphering key before each execution of the TMSI reallocation procedure to provide unlinkability. I

A Unlinkable Delegation-based Authentication Protocol with Users’ Non-repudiation for Portable Communication Systems

[[abstract]]For portable communication systems, the delegation-based authentication protocol provides efficient subsequent login authentication, data confidentiality, user privacy protection, and non-repudiation. However, in all proposed protocols, the non-repudiation of mobile users is based on an unreasonable assumption that home location registers are always trusted. To weaken this assumption and enhance the nonrepudiation of mobile users, a new delegation-based authentication protocol is proposed. The new protocol also removes the exhaustive search problem of the subsequent login authentication to improve the subsequent login authentication performance. Moreover, the user unlinkability in the subsequent login authentication is also provided to enhance the user identity privacy protection.[[incitationindex]]EI[[incitationindex]]CEPS[[booktype]]紙

Retrofitting Mutual Authentication to GSM Using RAND Hijacking

As has been widely discussed, the GSM mobile telephony system only offers unilateral authentication of the mobile phone to the network; this limitation permits a range of attacks. While adding support for mutual authentication would be highly beneficial, changing the way GSM serving networks operate is not practical. This paper proposes a novel modification to the relationship between a Subscriber Identity Module (SIM) and its home network which allows mutual authentication without changing any of the existing mobile infrastructure, including the phones; the only necessary changes are to the authentication centres and the SIMs. This enhancement, which could be deployed piecemeal in a completely transparent way, not only addresses a number of serious vulnerabilities in GSM but is also the first proposal for enhancing GSM authentication that possesses such transparency properties.Comment: 17 pages, 2 figure

MobileTrust: Secure Knowledge Integration in VANETs

Vehicular Ad hoc NETworks (VANET) are becoming popular due to the emergence of the Internet of Things and ambient intelligence applications. In such networks, secure resource sharing functionality is accomplished by incorporating trust schemes. Current solutions adopt peer-to-peer technologies that can cover the large operational area. However, these systems fail to capture some inherent properties of VANETs, such as fast and ephemeral interaction, making robust trust evaluation of crowdsourcing challenging. In this article, we propose MobileTrust—a hybrid trust-based system for secure resource sharing in VANETs. The proposal is a breakthrough in centralized trust computing that utilizes cloud and upcoming 5G technologies to provide robust trust establishment with global scalability. The ad hoc communication is energy-efficient and protects the system against threats that are not countered by the current settings. To evaluate its performance and effectiveness, MobileTrust is modelled in the SUMO simulator and tested on the traffic features of the small-size German city of Eichstatt. Similar schemes are implemented in the same platform to provide a fair comparison. Moreover, MobileTrust is deployed on a typical embedded system platform and applied on a real smart car installation for monitoring traffic and road-state parameters of an urban application. The proposed system is developed under the EU-founded THREAT-ARREST project, to provide security, privacy, and trust in an intelligent and energy-aware transportation scenario, bringing closer the vision of sustainable circular economy