Karl Norrman

Conversational IP multimedia security

With the introduction of 3G systems multimedia applications over wireless will become widely available to the general public. One such application will be peer-to-peer conversational multimedia communication in which voice, video, still pictures and other media can be used simultaneously and in an interactive way. However, in an all IP environment it is important to have high quality and efficient security services to protect the traffic against eavesdropping and manipulations. In particular, end-to-end security is considered attractive. This paper investigates the security requirements that emerge from conversational IP multimedia applications in heterogeneous environments, with special emphasis on the requirements stemming from the wireless access. The design and the design goals of both SRTP, a security protocol for protection of media traffic, and multimedia Internet keying (MIKEY), a key management protocol specially developed for those environments, are also described.

Formal Analysis of Security Procedures in LTE - A Feasibility Study

The only part of the Long Term Evolution (LTE) security standard that has been formally analyzed is the Authentication and Key Agreement (AKA) procedure. It is not clear how well existing security related verification tools can handle other types of procedures. In this work, we use ProVerif to analyze the procedures related to session management and mobility. Our analysis has shown that most of the secrecy and agreement properties hold which was expected. However, we had difficulties proving stronger injective agreement properties.

OpenSAW: Open Security Analysis Workbench

Software is today often composed of many sourced components, which potentially contain security vulnerabilities, and therefore require testing before being integrated. Tools for automated test case generation, for example, based on white-box fuzzing, are beneficial for this testing task. Such tools generally explore limitations of the specific underlying techniques for solving problems related to, for example, constraint solving, symbolic execution, search heuristics and execution trace extraction. In this article we describe the design of OpenSAW, a more flexible general-purpose white-box fuzzing framework intended to encourage research on new techniques identifying security problems. In addition, we have formalized two unaddressed technical aspects and devised new algorithms for these. The first relates to generalizing and combining different program exploration strategies, and the second relates to prioritizing execution traces. We have evaluated OpenSAW using both in-house and external programs and identified several bugs.

Subscription identifier privacy in 5G systems

Privacy is a main concern for mobile network users, and there are many proposed enhancements for the protection of the long-term subscription identifier. Some enhancements require asymmetric key operations, which increase both processing requirements and protocol message sizes. To the best of our knowledge, there has been no practical implementation feasibility study of these enhancements using commodity mobile devices. Neither is it clear whether the enhancements are sufficient. This paper highlights privacy weaknesses, when the long-term subscription identifier is used in Paging procedures, and proposes new ways to resolve these. Further, the paper evaluates an Android implementation of one of the enhancements, which includes the asymmetric scheme Elliptic Curve Integrated Encryption Scheme (ECIES). We conclude that it is feasible to implement asymmetric encryption methods for the long-term subscription identifier and that the highlighted privacy weaknesses can be efficiently countered. This removes another set of obstacles for realizing the protection in mobile network standards.