Key Agreement

WPA and WPA2 (Wi-Fi Protected Access) is a certification program developed by the Wi-Fi Alliance to indicate compliance with the security protocol created by the WiFi alliance to secure wireless networks. The alliance defined the protocol in response to several weaknesses researchers had found in the previous Wired Equivalent Privacy (WEP) system. Many sophisticated authentication and encryption techniques have been embedded into WPA but it is still facing a lot of challenging situations. In this paper we discuss the vulnerabilit

Analysing and attacking the 4-way handshake of IEEE 802.11i standard

The IEEE 802.11i standard has been designed to enhance security in wireless networks. In the 4-way handshake the supplicant and the authenticator use the pairwise master key (PMK) to derive a fresh pairwise transient key (PTK). The PMK is not used directly for security while assuming the supplicant and authenticator have the same PMK before running 4-way handshake. In this paper, the 4-way handshake phase has been analysed using Isabelle tool to identify a new Denial-of-Service (DoS) attack. The attack prevents the authenticator from receiving message 4 after the supplicant sends it out. This attack forces the authenticator to re-send the message 3 until time out and subsequently to de-authenticate supplicant. This paper has proposed improvements to the 4-way handshake to avoid the Denial-of-Service attack

Versatile Extensible Security System for Mobile Ad Hoc Networks

Mobile Ad hoc Network (MANET) is becoming more and more popular in scientific, government, and general applications, but security system for MANET is still at infant stage. Currently, there are not many security systems that provide extensive security coverage for MANET. Moreover, most of these security systems assume nodes have infinite computation power and energy; an assumption that is not true for many mobiles. Versatile and Extensible System (VESS) is a powerful and versatile general-purpose security suite that comprises of modified versions of existing encryption and authentication schemes. VESS uses a simple and network-efficient but still reliable authentication scheme. The security suite offers four levels of security adjustments base on different encryption strength. Each level is designed to suit different network needs (performance and/or security), and the security suite allows individual end-to-end pair-wise security level adjustments; a big advantage for highly heterogeneous network. This versatility and adjustability let each pair of talking nodes in the network can choose a security level that prioritize either performance or security, or nodes can also choose a level that carefully balance between security strength and network performance. Finally, the security suite, with its existing authentication and encryption systems, is a framework that allows easy future extension and modification

Wireless LAN security.

Chan Pak To Patrick.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 82-86).Abstracts in English and Chinese.Abstract --- p.iAcknowledgement --- p.iiiContents --- p.ivList of Figures --- p.viiList of Tables --- p.viiiChapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.2 --- The Problems --- p.3Chapter 1.3 --- My Contribution --- p.4Chapter 1.4 --- Thesis Organization --- p.5Chapter 2 --- Wireless LAN Security Model --- p.6Chapter 2.1 --- Preliminary Definitions on WLAN --- p.6Chapter 2.2 --- Security Model --- p.7Chapter 2.2.1 --- Security Attributes --- p.7Chapter 2.2.2 --- Security Threats in WLAN --- p.8Chapter 2.2.3 --- Attacks on Authentication Scheme --- p.10Chapter 2.2.4 --- Attacks on Keys --- p.10Chapter 2.3 --- Desired Properties of WLAN Authentication --- p.11Chapter 2.3.1 --- Security Requirements of WLAN Authentication --- p.11Chapter 2.3.2 --- Security Requirements of Session Keys --- p.12Chapter 2.3.3 --- Other Desired Properties of WLAN Authentication --- p.12Chapter 3 --- Cryptography --- p.14Chapter 3.1 --- Overview on Cryptography --- p.14Chapter 3.2 --- Symmetric-key Encryption --- p.15Chapter 3.2.1 --- Data Encryption Standard (DES) --- p.15Chapter 3.2.2 --- Advanced Encryption Standard (AES) --- p.15Chapter 3.2.3 --- RC4 --- p.16Chapter 3.3 --- Public-key Cryptography --- p.16Chapter 3.3.1 --- RSA Problem and Related Encryption Schemes --- p.17Chapter 3.3.2 --- Discrete Logarithm Problem and Related Encryption Schemes --- p.18Chapter 3.3.3 --- Elliptic Curve Cryptosystems --- p.19Chapter 3.3.4 --- Digital Signature --- p.19Chapter 3.4 --- Public Key Infrastructure --- p.20Chapter 3.5 --- Hash Functions and Message Authentication Code --- p.21Chapter 3.5.1 --- SHA-256 --- p.22Chapter 3.5.2 --- Message Authentication Code --- p.22Chapter 3.6 --- Entity Authentication --- p.23Chapter 3.6.1 --- ISO/IEC 9798-4 Three-pass Mutual --- p.23Chapter 3.6.2 --- ISO/IEC 9798-4 One-pass Unilateral --- p.24Chapter 3.7 --- Key Establishment --- p.24Chapter 3.7.1 --- Diffie-Hellman Key Exchange --- p.24Chapter 3.7.2 --- Station-to-Station Protocol --- p.25Chapter 3.8 --- Identity-Based Cryptography --- p.25Chapter 3.8.1 --- The Boneh-Franklin Encryption Scheme --- p.26Chapter 3.8.2 --- Au and Wei's Identification Scheme and Signature Scheme --- p.27Chapter 4 --- Basics of WLAN Security and WEP --- p.29Chapter 4.1 --- Basics of WLAN Security --- p.29Chapter 4.1.1 --- "Overview on ""Old"" WLAN Security" --- p.29Chapter 4.1.2 --- Some Basic Security Measures --- p.29Chapter 4.1.3 --- Virtual Private Network (VPN) --- p.30Chapter 4.2 --- WEP --- p.31Chapter 4.2.1 --- Overview on Wired Equivalent Privacy (WEP) --- p.31Chapter 4.2.2 --- Security Analysis on WEP --- p.33Chapter 5 --- IEEE 802.11i --- p.38Chapter 5.1 --- Overview on IEEE 802.11i and RSN --- p.38Chapter 5.2 --- IEEE 802.1X Access Control in IEEE 802.11i --- p.39Chapter 5.2.1 --- Participants --- p.39Chapter 5.2.2 --- Port-based Access Control --- p.40Chapter 5.2.3 --- EAP and EAPOL --- p.40Chapter 5.2.4 --- RADIUS --- p.41Chapter 5.2.5 --- Authentication Message Exchange --- p.41Chapter 5.2.6 --- Security Analysis --- p.41Chapter 5.3 --- RSN Key Management --- p.43Chapter 5.3.1 --- RSN Pairwise Key Hierarchy --- p.43Chapter 5.3.2 --- RSN Group Key Hierarchy --- p.43Chapter 5.3.3 --- Four-way Handshake and Group Key Handshake --- p.44Chapter 5.4 --- RSN Encryption and Data Integrity --- p.45Chapter 5.4.1 --- TKIP --- p.45Chapter 5.4.2 --- CCMP --- p.46Chapter 5.5 --- Upper Layer Authentication Protocols --- p.47Chapter 5.5.1 --- Overview on the Upper Layer Authentication --- p.47Chapter 5.5.2 --- EAP-TLS --- p.48Chapter 5.5.3 --- Other Popular ULA Protocols --- p.50Chapter 6 --- Proposed IEEE 802.11i Authentication Scheme --- p.52Chapter 6.1 --- Proposed Protocol --- p.52Chapter 6.1.1 --- Overview --- p.52Chapter 6.1.2 --- The AUTHENTICATE Protocol --- p.56Chapter 6.1.3 --- The RECONNECT Protocol --- p.59Chapter 6.1.4 --- Packet Format --- p.61Chapter 6.1.5 --- Ciphersuites Negotiation --- p.64Chapter 6.1.6 --- Delegation --- p.64Chapter 6.1.7 --- Identity Privacy --- p.68Chapter 6.2 --- Security Considerations --- p.68Chapter 6.2.1 --- Security of the AUTHENTICATE protocol --- p.68Chapter 6.2.2 --- Security of the RECONNECT protocol --- p.69Chapter 6.2.3 --- Security of Key Derivation --- p.70Chapter 6.2.4 --- EAP Security Claims and EAP Methods Requirements --- p.72Chapter 6.3 --- Efficiency Analysis --- p.76Chapter 6.3.1 --- Overview --- p.76Chapter 6.3.2 --- Bandwidth Performance --- p.76Chapter 6.3.3 --- Computation Speed --- p.76Chapter 7 --- Conclusion --- p.79Chapter 7.1 --- Summary --- p.79Chapter 7.2 --- Future Work --- p.80Bibliography --- p.8

Support for Wireless LAN Design

As mobile devices become common in mainstream computing, it becomes imperative to effectively design computing architectures that seamlessly and effectively integrate them. Rapid advancements in wireless technology has made it possible to build efficient wireless local area networks (WLANs). Designing WLANs presents some unique challenges. Some heuristics are available for WLAN design, but they represent piecemeal solutions, focusing on a limited set of issues. This paper provides a more comprehensive approach to WLAN design, by providing support for additional tasks in the design process, as well as by providing the designer the option of examining multiple competing options. The approach is developed in modular fashion, thereby permitting the easy substitution of alternative models in any phase of the process. We believe the approach to be useful for WLAN designers, and it provides an apt illustration of design science in information systems research

Practical privacy enhancing technologies for mobile systems

Mobile computers and handheld devices can be used today to connect to services available on the Internet. One of the predominant technologies in this respect for wireless Internet connection is the IEEE 802.11 family of WLAN standards. In many countries, WLAN access can be considered ubiquitous; there is a hotspot available almost anywhere. Unfortunately, the convenience provided by wireless Internet access has many privacy tradeoffs that are not obvious to mobile computer users. In this thesis, we investigate the lack of privacy of mobile computer users, and propose practical enhancements to increase the privacy of these users. We show how explicit information related to the users' identity leaks on all layers of the protocol stack. Even before an IP address is configured, the mobile computer may have already leaked their affiliation and other details to the local network as the WLAN interface openly broadcasts the networks that the user has visited. Free services that require authentication or provide personalization, such as online social networks, instant messengers, or web stores, all leak the user's identity. All this information, and much more, is available to a local passive observer using a mobile computer. In addition to a systematic analysis of privacy leaks, we have proposed four complementary privacy protection mechanisms. The main design guidelines for the mechanisms have been deployability and the introduction of minimal changes to user experience. More specifically, we mitigate privacy problems introduced by the standard WLAN access point discovery by designing a privacy-preserving access-point discovery protocol, show how a mobility management protocol can be used to protect privacy, and how leaks on all layers of the stack can be reduced by network location awareness and protocol stack virtualization. These practical technologies can be used in designing a privacy-preserving mobile system or can be retrofitted to current systems

Efficient Security Protocols for Fast Handovers in Wireless Mesh Networks

Wireless mesh networks (WMNs) are gaining popularity as a flexible and inexpensive replacement for Ethernet-based infrastructures. As the use of mobile devices such as smart phones and tablets is becoming ubiquitous, mobile clients should be guaranteed uninterrupted connectivity and services as they move from one access point to another within a WMN or between networks. To that end, we propose a novel security framework that consists of a new architecture, trust models, and protocols to offer mobile clients seamless and fast handovers in WMNs. The framework provides a dynamic, flexible, resource-efficient, and secure platform for intra-network and inter-network handovers in order to support real-time mobile applications in WMNs. In particular, we propose solutions to the following problems: authentication, key management, and group key management. We propose (1) a suite of certificate-based authentication protocols that minimize the authentication delay during handovers from one access point to another within a network (intra-network authentication). (2) a suite of key distribution and authentication protocols that minimize the authentication delay during handovers from one network to another (inter-network authentication). (3) a new implementation of group key management at the data link layer in order to reduce the group key update latency from linear time (as currently done in IEEE 802.11 standards) to logarithmic time. This contributes towards minimizing the latency of the handover process for mobile members in a multicast or broadcast group

Securing Handover in Wireless IP Networks

In wireless and mobile networks, handover is a complex process that involves multiple layers of protocol and security executions. With the growing popularity of real time communication services such as Voice of IP, a great challenge faced by handover nowadays comes from the impact of security implementations that can cause performance degradation especially for mobile devices with limited resources. Given the existing networks with heterogeneous wireless access technologies, one essential research question that needs be addressed is how to achieve a balance between security and performance during the handover. The variations of security policy and agreement among different services and network vendors make the topic challenging even more, due to the involvement of commercial and social factors. In order to understand the problems and challenges in this field, we study the properties of handover as well as state of the art security schemes to assist handover in wireless IP networks. Based on our analysis, we define a two-phase model to identify the key procedures of handover security in wireless and mobile networks. Through the model we analyze the performance impact from existing security schemes in terms of handover completion time, throughput, and Quality of Services (QoS). As our endeavor of seeking a balance between handover security and performance, we propose the local administrative domain as a security enhanced localized domain to promote the handover performance. To evaluate the performance improvement in local administrative domain, we implement the security protocols adopted by our proposal in the ns-2 simulation environment and analyze the measurement results based on our simulation test

Context transfer support for mobility management in all-IP networks.

This thesis is a description of the research undertaken in the course of the PhD and evolves around a context transfer protocol which aims to complement and support mobility management in next generation mobile networks. Based on the literature review, it was identified that there is more to mobility management than handover management and the successful change of routing paths. Supportive mechanisms like fast handover, candidate access router discovery and context transfer can significantly contribute towards achieving seamless handover which is especially important in the case of real time services. The work focused on context transfer motivated by the fact that it could offer great benefits to session re-establishment during the handover operation of a mobile user and preliminary testbed observations illustrated the need for achieving this. Context transfer aims to minimize the impact of certain transport, routing, security-related services on the handover performance. When a mobile node (MN) moves to a new subnet it needs to continue such services that have already been established at the previous subnet. Examples of such services include AAA profile, IPsec state, header compression, QoS policy etc. Re-establishing these services at the new subnet will require a considerable amount of time for the protocol exchanges and as a result time- sensitive real-time traffic will suffer during this time. By transferring state to the new domain candidate services will be quickly re-established. This would also contribute to the seamless operation of application streams and could reduce susceptibility to errors. Furthermore, re-initiation to and from the mobile node will be avoided hence wireless bandwidth efficiency will be conserved. In this research an extension to mobility protocols was proposed for supporting state forwarding capabilities. The idea of forwarding states was also explored for remotely reconfiguring middleboxes to avoid any interruption of a mobile users' sessions or services. Finally a context transfer module was proposed to facilitate the integration of such a mechanism in next generation architectures. The proposals were evaluated analytically, via simulations or via testbed implementation depending on the scenario investigated. The results demonstrated that the proposed solutions can minimize the impact of security services like authentication, authorization and firewalls on a mobile user's multimedia sessions and thus improving the overall handover performance