Security and Privacy in Emerging Communication Standards

Haibat Khan

Research output: ThesisDoctoral Thesis

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5G networks are the next generation of mobile telephony systems, offering faster speeds, more reliable connections and a platform for various vertical industries. However, 5G also comes with potentially enormous privacy risks. It is therefore crucial for a successful 5G future that these privacy issues be resolved at the earliest. This thesis examines the current state of subscription privacy in 5G and highlights outstanding privacy problems and viable approaches to their resolution.

One of the most pressing privacy concerns in mobile networks relates to the exposure of the subscribers' permanent identifier, known as IMSI-catching attack. Since these identifiers uniquely identify the subscribers, malicious third parties in the past have misused their exposure to physically locate and track subscribers. Although 3GPP, the defacto international body for mobile telephony standardization, has introduced a public-key based protection mechanism to counter this threat in 5G, the proposed solution is marred with various shortcomings. Keeping in view the long-term deployment timeframes of 5G, the most significant of these shortcomings is the insecurity of the proposed mechanism against a quantum adversary. This technical problem of private identification in 5G remains open in symmetric-key settings; i.e. does there exist an efficient symmetric-key solution for private identification in 5G? This thesis answers this question positively and presents an alternative private identification scheme for 5G that works within the symmetric-key domain and overcomes the other limitations of the existing 3GPP scheme.

Another potent threat to 5G privacy is that of downgrade attacks, where a fake base station forces the connection down to one of the previous generations and then exploits the existing privacy vulnerabilities. Keeping this threat in mind, this thesis also explores the feasibility of combining the symmetric private identification scheme with a recent downgrade protection proposal to come up with a 5G identification mechanism that is both quantum-secure and downgrade-resistant.

This problem of private identification within the symmetric-key domain is of interest in other application areas too. The techniques utilized for the 5G private identification scheme are further extended to address the problem of key establishment for Wireless Body Area Networks (WBANs) in a privacy-preserving manner without resorting to public-key cryptography. This is significant because the nodes in a WBAN are energy constrained and require battery-efficient security solutions. Moreover, by avoiding public-key cryptography, a quantum-secure key agreement solution with advance security properties for the WBAN standard IEEE Std 802.15.6 is achieved.
Original languageEnglish
Awarding Institution
  • Royal Holloway, University of London
  • Martin, Keith M., Supervisor
Award date1 Nov 2020
Publication statusUnpublished - 2020


  • 5G
  • international security standards
  • mobile telephony
  • Privacy
  • Privacy Preserving

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