Showing papers by "Chris J. Mitchell published in 2003"

A taxonomy of single sign-on systems

Abstract: At present, network users have to manage one set of authentication credentials (usually a username/password pair) for every service with which they are registered Single Sign-On (SSO) has been proposed as a solution to the usability, security and management implications of this situation Under SSO, users authenticate themselves only once and are logged into the services they subsequently use without further manual interaction Several architectures for SSO have been developed, each with different properties and underlying infrastructures This paper presents a taxonomy of these approaches and puts some of the SSO schemes, services and products into that context This enables decisions about the design and selection of future approaches to SSO to be made within a more structured context; it also reveals some important differences in the security properties that can be provided by various approaches

Forward and backward blocking of causal judgment is enhanced by additivity of effect magnitude

Abstract: When two causes for a given effect are simultaneously presented, it is natural to expect an effect of greater magnitude. However many laboratory tasks preclude such an additivity rule by imposing a ceiling on effect magnitude—for example, by using a binary outcome. Under these conditions, a compound of two causal cues cannot be distinguished from a compound of one causal cue and one noncausal cue. Two experiments tested the effect of additivity on cue competition. Significant but weak forward blocking and no backward blocking were observed in a conventional “allergy” causal judgment task. Explicit pretraining of magnitude additivity produced strong and significant forward and backward blocking. Additivity pretraining was found to be unnecessary for another cue competition effect, release from overshadowing, which does not logically depend on additivity. The results confirm that blocking is constrained when effect magnitude is constrained and provide support for an inferential account of cue competition.

Reputation methods for routing security for mobile ad hoc networks

Abstract: Mobile ad hoc networks have inherently very different properties to conventional networks. These new characteristics present major security vulnerabilities; in particular, one side effect of the unique way in which routing protocols operate in ad hoc networks is that many new threats arise. Selfish nodes are those which do not perform certain operations that the protocol specifies that they should, through a wish to conserve power. Malicious nodes may deliberately disrupt the network using a variety of attacks. The paper discusses reputation mechanisms which have been suggested as a means to mitigate the detrimental effect of selfish and malicious nodes. The paper reveals reasons why complex reputation systems may be too inefficient to use in a mobile ad hoc network, where resources are limited. However, suggestions are also made to show how a simple reputation system might be used to enhance the robustness of ad hoc networks.

Acquired equivalence and distinctiveness in human discrimination learning: evidence for associative mediation.

Abstract: In the first stage of Experiments 1-3, subjects learned to associate different geometrical figures with colors or with verbal labels. Performance in Stage 2, in which the figures signaled which of 2 motor responses should be performed, was superior in subjects required to make the same response to figures that had shared the same Stage 1 associate. A third stage of testing showed that the events used as associates in Stage 1 were capable of evoking the motor response trained in Stage 2, an outcome predicted by an associative interpretation of such transfer effects. Experiment 4 provided evidence that the relevant associations can be effective in controlling motor responding even when subjects report an antagonistic relationship between the events.

Single Sign-On Using Trusted Platforms

Abstract: At present, network users have to remember a username and a corresponding password for every service with which they are registered. One solution to the security and usability implications of this situation is Single Sign-On, whereby the user authenticates only once to an ‘Authentication Service Provider’ (ASP) and subsequently uses disparate Service Providers (SPs) without necessarily re-authenticating. The information about the user’s authentication status is handled between the ASP and the desired SP transparently to the user. This paper describes a method by which the end-user’s computing platform itself plays the role of the ASP. The platform has to be a Trusted Platform conforming to the Trusted Computing Platform Alliance (TCPA) specifications. The relevant TCPA architectural components and security services are described and associated threats are analysed.

Security Vulnerabilities in Ad Hoc Networks

Abstract: Mobile ad hoc networks have inherently different properties than traditional wired networks. These new characteristics present different security vulnerabilities and this paper provides a detailed classification of these threats. Threats exist to a mobile ad hoc network both from external nodes unauthorised to participate in the mobile ad hoc networks, and from internal nodes, which have the authorisation credentials to participate in the mobile ad hoc network. Internal nodes giving rise to threats can be further divided according to their behaviour — failed, badly failed, selfish and malicious nodes. Failed and selfish nodes are those which do not perform certain operations that the protocol specifies that they should, the former due to some unforeseen failure and the latter due to selfishness to conserve power. Badly failed nodes may perform operations incorrectly, introducing false and misleading information into the network. Malicious nodes may deliberately disrupt the network using a variety of attacks. All categories of node behaviour should be considered when designing protocols for mobile ad hoc networks.

Remote user authentication using public information

Abstract: A method for remote user authentication is proposed that requires only public information to be stored at the verifying host. Like the S/KEY scheme, the new technique uses only symmetric cryptography and is resistant to eavesdropping, but, unlike S/KEY, it is resistant to host impersonation attacks. The avoidance of asymmetric cryptographic techniques makes the scheme appropriate for low cost user authentication devices.

Security for Mobility

Abstract: * Part I: Underlying technologies * Chapter 1: Cryptography for mobile security * Chapter 2: PKI in mobile systems * Chapter 3: The personal PKI * Chapter 4: The smartcard as a mobile security device * Chapter 5: Secure mobile tokens - the future * Part II: Network security * Chapter 6: UMTS security * Chapter 7: Securing network access in future mobile systems * Chapter 8: Public key based network access * Chapter 9: Security in personal area networks * Chapter 10: Towards the security of routing in ad hoc networks * Chapter 11: Security issues in a MobileIPv6 network * Part III: Mobile code issues * Chapter 12: Security for agent systems and mobile agents * Chapter 13: Security issues for downloaded code in mobile phones * Part IV: Application security * Chapter 14: Secure mobile commerce * Chapter 15: Securing the delivery of digital content over the Internet * Chapter 16: Security for future standardised DRM * Part V: The future * Chapter 17: Pioneering advanced mobile privacy and security

Security Protocols for Biometrics-Based Cardholder Authentication in Smartcards

Abstract: The use of biometrics, and fingerprint recognition in particular, for cardholder authentication in smartcard systems is growing in popularity, and such systems are the focus of this paper. In such a biometrics-based cardholder authentication system, sensitive data will typically need to be transferred between the smartcard and the card reader. We propose strategies to ensure integrity of the sensitive data exchanged between the smartcard and the card reader during authentication of the cardholder to the card, and also to provide mutual authentication between card and reader. We examine two possible types of attacks: replay attacks and active attacks in which an attacker is able to calculate hashes and modify messages accordingly.

Using GSM/UMTS for single sign-on

Abstract: At present, network users have to remember a user-name and a corresponding password for every service with which they are registered. Single sign-on (SSO) has been proposed as a solution to the usability, security and management implications of this situation. Under SSO, users authenticate themselves only once to an entity termed the 'authentication service provider' (ASP) and subsequently use disparate service providers (SPs) without re-authenticating. The information about the user's authentication status is handled between the ASP and the desired SP in a manner transparent to the user. We propose an SSO protocol where a GSM or UMTS operator plays the role of the ASP and by which its subscribers can be authenticated to SPs without any user interaction and in a way that preserves the user's privacy and mobility. The protocol requires only minimal changes to the deployed GSM infrastructure.

On the security of XCBC, TMAC and OMAC

Abstract: The security provided by the XCBC, TMAC and OMAC schemes is analysed and compared with other MAC schemes. The results imply that there is relatively little to be gained practically through the introduction of these schemes by comparison with other well-established MAC functions. Moreover, TMAC and OMAC possess design weaknesses which enable part of the secret key to be recovered much more easily than would ideally be the case — design changes are suggested which alleviate this problem. Whether or not the proofs of security are retrievable for the modified designs remains an open question, although the need for change would appear to be clear.

Enhancing E-commerce Security Using GSM Authentication

Abstract: Today, e-commerce transactions are typically protected using SSL/TLS\@. However, there are risks in such use of SSL/TLS, notably threats arising from the fact that information is stored in clear at the end point of the communication link and the lack of user authentication. Although SSL/TLS does offer the latter, it is optional and usually omitted since users typically do not have the necessary asymmetric key pair. In this paper, we propose a payment protocol in which user authentication is provided using GSM ‘subscriber identity authentication’. In the protocol, a consumer is required to possess a GSM mobile station registered under a subscriber name corresponding to that on his/her debit/credit card. The cardholder identity is combined with the GSM subscriber identity in such a way that without a mobile station, in particular the SIM, and the corresponding debit/credit card, an unscrupulous user will find it difficult to make a fraudulent payment at the expense of the legitimate cardholder. This is achieved in such a way that no management overhead is imposed on the user.

Single sign-on using trusted platforms

Abstract: At present, network users have to remember a username and a corresponding password for every service with which they are registered. One solution to the security and usability implications of this situation is Single Sign-On, whereby the user authenticates only once to an 'Authentication Service Provider' (ASP) and subsequently uses disparate Service Providers (SPs) without necessarily re-authenticating. The information about the user's authentication status is handled between the ASP and the desired SP transparently to the user. This paper describes a method by which the end-user's computing platform itself plays the role of the ASP. The platform has to be a Trusted Platform conforming to the Trusted Computing Platform Alliance (TCPA) specifications. The relevant TCPA architectural components and security services are described and associated threats are analysed.

A Secure Electronic Murabaha Transaction

Abstract: Conventional credit card transactions are not consistent with Islamic principles, as exemplified by the Islamic banking system and the ‘Murabaha sale’. Thus, if Islamic principles are to be applied to e-commerce, where credit card transactions are the norm, a new and secure electronic payment process is required. In this paper we present a method for secure electronic Murabaha transactions. After introducing the notion of Murabaha sale within the Islamic banking framework, we describe a general model for a secure electronic Murabaha transaction, and then consider the associated security risks. Security requirements are then identified for a secure electronic Murabaha transaction. We then present the Secure Electronic Murabaha Transaction (SEMT), designed to address the identified security requirements. Finally, we analyse how the proposed protocol matches the identified security requirements.

Key recovery attack on ANSI retail MAC

Abstract: A new type of attack is introduced which takes advantage of message authentication code (MAC) truncation to simplify key recovery attacks based on MAC verifications. One example of the attack is described which, in certain circumstances, enables a more efficient attack than was previously known to be launched against the ANSI retail MAC. The existence of this attack means that truncation for this MAC scheme should be used with greater care than was previously believed, and very short MACs should be avoided altogether.

Securing FIPA Agent Communication.

Abstract: The agent paradigm has been the subject of much research during the last decade Recently, security of multiagent systems has gained increased attention In this paper we consider the FIPA agent communication specifications from a security perspective, and outline how security functionality can be added Keywords— security, multi-agent system, communication, FIPA

PANA/GSM authentication for Internet access

Abstract: Currently, there are no Internet access authentication protocols available that are lightweight, can be carried over arbitrary access networks, and are flexible enough to be used in all the likely future ubiquitous mobility access contexts. The IETF PANA (Protocol for carrying Authentication for Network Access) work aims to provide a protocol that will be a network-layer authentication carrier for access networks that support IP. The article proposes a PANA/GSM authentication protocol for heterogeneous network access as a step towards filling this gap. A security analysis of the PANA/GSM protocol is also provided. The article aims primarily at contributing to the design of authentication protocols suitable for use in future heterogeneous Internet access environments supporting ubiquitous mobility.

Truncation attacks on MACs

Abstract: A new type of attack on message authentication codes (MACs) is introduced which takes advantage of possible weaknesses in interfaces to hardware security modules. In particular, if a module does not fix the degree of MAC truncation employed, then potentially serious attacks are possible.

Using constraints to protect personal location information

Abstract: This paper assesses the possible use of constraints to control the dissemination and use of location information (LI) within a location based service architecture. The various types of constraint which may by required are also considered. Finally, issues and risks with the possible use of constraints are discussed, as are possible solutions to these hazards.

PKI implementation issues in B2B e-commerce

Abstract: The security of sensitive information transmitted and stored during ecommerce transactions is clearly an overriding issue of concern to organisations and individuals. Not only is there a need for the protection of the confidentiality and integrity of sensitive information, but verification of the identity of a communicating party is often also necessary. Public Key Infrastructures or PKIs have long been promoted as an important part of a solution to these concerns, since they support the wide scale use of public key cryptography to fulfil end-user security requirements. Although PKIs involving a single CA are effective when implemented within a well-defined population, the implementation of PKIs across multiple domains and hence involving multiple CAs, e.g. as required for e-commerce, has encountered serious problems. The intention of this paper is to discuss the main reasons for the PKI implementation issues in B2B e-commerce and to propose potential solutions.

PANA/IKEv2: An Internet authentication protocol for heterogeneous access

Abstract: Currently there are no Internet access authentication protocols available that support both symmetric and asymmetric cryptographic techniques, can be carried over arbitrary access networks, and are flexible enough to be re-used in all the likely future ubiquitous mobility access contexts. This article proposes the PANA/IKEv2 authentication protocol for heterogeneous network access as a step towards filling this gap. A security analysis of the PANA/IKEv2 protocol is also provided. This article aims primarily at contributing to the design of authentication protocols suitable for use in future heterogeneous Internet access environments supporting ubiquitous mobility.

Security protocols for biometrics-based cardholder authentication in smartcards

Abstract: The use of biometrics, and fingerprint recognition in particular, for cardholder authentication in smartcard systems is growing in popularity, and such systems are the focus of this paper. In such a biometrics-based cardholder authentication system, sensitive data will typically need to be transferred between the smartcard and the card reader. We propose strategies to ensure integrity of the sensitive data exchanged between the smartcard and the card reader during authentication of the cardholder to the card, and also to provide mutual authentication between card and reader. We examine two possible types of attacks: replay attacks and active attacks in which an attacker is able to calculate hashes and modify messages accordingly.

A Secure Electronic Payment Scheme for Charity Donations

Abstract: Although many charities have a web presence, almost all of them have been designed to accept credit cards as the only means for making donations. The anonymity requirements of many donors, however, make the existing means of donation inappropriate for them. In this paper we investigate the business need for an internet charity donation scheme, identify the security requirements such a scheme should fulfill, and propose a scheme that uses an anonymous electronic cash technique to make donations, and that employs smart cards for donation distribution. Finally, we analyse how the proposed scheme matches the identified security requirements.

Comment: Property of finite fields and its cryptographic application

Abstract: The “new” property of finite fields given by Wei Baodian et al. is a well-known fundamental result in finite field theory.