Yu-Jen Chen

Bio: Yu-Jen Chen is an academic researcher from National Chiao Tung University. The author has contributed to research in topics: Block cipher & Message authentication code. The author has an hindex of 1, co-authored 1 publications receiving 78 citations.

Secure communication mechanisms for GSM networks

Abstract: With the advance of wireless communications technology, mobile communications has become more convenient than ever. However, because of the openness of wireless communications, the protection of the privacy between communicating parties is becoming a very important issue. We focus on the security of the Global System for Mobile communication (GSM) networks. A secure communication architecture for the GSM network is proposed. In the proposed architecture, we use public-key cryptography for user authentication and stream cipher for message encryption and decryption. An authentication protocol and a key generation method are presented in conjunction with the proposed architecture. Cryptanalysis and operational analysis show that the authentication protocol is secure and efficient. Simulation results indicate that the key generation method can always produce key strings of evenly distributed 0s and 1s and with infinite period.

On cellular botnets: measuring the impact of malicious devices on a cellular network core

Abstract: The vast expansion of interconnectivity with the Internet and the rapid evolution of highly-capable but largely insecure mobile devices threatens cellular networks. In this paper, we characterize the impact of the large scale compromise and coordination of mobile phones in attacks against the core of these networks. Through a combination of measurement, simulation and analysis, we demonstrate the ability of a botnet composed of as few as 11,750 compromised mobile phones to degrade service to area-code sized regions by 93%. As such attacks are accomplished through the execution of network service requests and not a constant stream of phone calls, users are unlikely to be aware of their occurrence. We then investigate a number of significant network bottlenecks, their impact on the density of compromised nodes per base station and how they can be avoided. We conclude by discussing a number of countermeasures that may help to partially mitigate the threats posed by such attacks.

Bluetooth telemedicine Processor for multichannel biomedical signal transmission via mobile cellular networks

Abstract: One of the emerging issues in m-Health is how best to exploit the mobile communications technologies that are now almost globally available. The challenge is to produce a system to transmit a patient's biomedical signals directly to a hospital for monitoring or diagnosis, using an unmodified mobile telephone. The paper focuses on the design of a processor, which samples signals from sensors on the patient. It then transmits digital data over a Bluetooth link to a mobile telephone that uses the General Packet Radio Service. The modular design adopted is intended to provide a "future-proofed" system, whose functionality may be upgraded by modifying the software.

Solutions to the GSM Security Weaknesses

Abstract: Recently, the mobile industry has experienced an extreme increment in number of its users. The GSM network with the greatest worldwide number of users succumbs to several security vulnerabilities. Although some of its security problems are addressed in its upper generations, there are still many operators using 2G systems. This paper briefly presents the most important security flaws of the GSM network and its transport channels. It also provides some practical solutions to improve the security of currently available 2G systems.

A new delegation-based authentication protocol for use in portable communication systems

Abstract: Portable communication systems (PCSs) provide a convenient means of communication; however, many problems arise relating to data security, user privacy, computational load, and communicational efficiency. To provide solutions for these problems, we introduce the concept of delegation into the wireless communication system. This new model makes our scheme an especially valuable improvement to portable communication systems.

Extension of authentication protocol for GSM

Abstract: An extension of the authentication protocol for GSM is proposed to improve some drawbacks of the current GSM authentication protocol including: not supporting bilateral authentication; huge bandwidth consumption between VLR and HLR; stored space overhead in VLR; and overloaded HLR with authentication of mobile stations. As a result, this new extension of the authentication protocol not only improves these drawbacks but also achieves the requirements: mutual authentication, reduction of bandwidth consumption, less storage of VLR database, security, and efficiency. The merit of the proposed protocol is that it does not cause problems and alter the existing architecture of GSM at all. The robustness of the new protocol is also based on security algorithms A3, A5 and A8.