AUTOMATED TRUST NEGOTIATION USING CRYPTOGRAPHIC CREDENTIALS

In automated trust negotiation (ATN), two parties exchange digitally signed credentials that contain attribute information to establish trust and make access control decisions. Because the information in question is often sensitive, credentials are protected according to access control policies. In traditional ATN, credentials are transmitted either in their entirety or not at all. This approach can at times fail unnecessarily, either because a cyclic dependency makes neither negotiator willing to reveal her credential before her opponent, because the opponent must be authorized for all attributes packaged together in a credential to receive any of them, or because it is necessary to fully disclose the attributes, rather than merely proving they satisfy some predicate (such as being over 21 years of age). Recently, several cryptographic credential schemes and associated protocols have been developed to address these and other problems. However, they can be used only as fragments of an ATN process. This paper introduces a framework for ATN in which the diverse credential schemes and protocols can be combined, integrated, and used as needed. A policy language is introduced that enables negotiators to specify authorization requirements that must be met by an opponent to receive various amounts of information about certified attributes and the credentials that contain it. The language also supports the use of uncertified attributes, allowing them to be required as part of policy satisfaction, and to place their (automatic) disclosure under policy control

Privacy-Preserving Trust Management Mechanisms from Private Matching Schemes

Cryptographic primitives are essential for constructing privacy-preserving communication mechanisms. There are situations in which two parties that do not know each other need to exchange sensitive information on the Internet. Trust management mechanisms make use of digital credentials and certificates in order to establish trust among these strangers. We address the problem of choosing which credentials are exchanged. During this process, each party should learn no information about the preferences of the other party other than strictly required for trust establishment. We present a method to reach an agreement on the credentials to be exchanged that preserves the privacy of the parties. Our method is based on secure two-party computation protocols for set intersection. Namely, it is constructed from private matching schemes.Comment: The material in this paper will be presented in part at the 8th DPM International Workshop on Data Privacy Management (DPM 2013

ACHIEVING AVAILABILITY AND DATA INTEGRITY PROOF IN HIERARCHICAL ATTRIBUTE ENCRYPTION SCHEME USING HYBRID CLOUD

It has been widely observed that the concept of cloud computing has become one of the major theory in the world of IT industry. Data owner decides to release their burden of storing and maintaining the data locally by storing it over the cloud. Cloud storage moves the owner’s data to large data centers which are remotely located on which data owner does not have any control. However, this unique feature of the cloud poses many new security challenges. One of the important concerns that need to be addressed is access control and integrity of outsourced data in cloud. Number of schemes has been proposed to achieve the access control of outsourced data like hierarchical attribute set based encryption [HASBE] by extending cipher-text-policy attribute set based encryption [CP-ABE]. Even though HASBE scheme achieves scalability, flexibility and fine grained access control, it fails to prove the data integrity in the cloud. Hence integrity checking concept has been proposed for HASBE scheme to achieve integrity. Though the scheme achieves integrity it fails to provide the availability of data to the user even when fault had occurred to data in the cloud. However, the fact that owner no longer have physical possession of data indicates that they are facing a potentially formidable risk for missing or corrupted data, because sometimes the cloud service provider deletes the data which are either not used by client from long-time and which occupies large space in the cloud without the knowledge or permission of data owner. Hence in order to avoid this security risk, in this paper we propose a hybrid cloud concept. Hybrid cloud is a cloud computing environment in which an organization provides and manages some internal resources and external resources. A hybrid cloud is a composition of at least one private cloud and at least one public cloud. This concept provides the availability and data integrity proof for HASBE scheme

Secure set-based policy checking and its application to password registration

Policies are the corner stones of today's computer systems. They define secure states and safe operations. A common problem with policies is that their enforcement is often in con ict with user privacy. In order to check the satisfiability of a policy, a server usually needs to collect from a client some information which may be private. In this work we introduce the notion of secure set-based policy checking (SPC) that allows the server to verify policies while preserving the client's privacy. SPC is a generic protocol that can be applied in many policy-based systems. As an example, we show how to use SPC to build a password registration protocol so that a server can check whether a client's password is compliant with its password policy without seeing the password. We also analyse SPC and the password registration protocol and provide security proofs. To demonstrate the practicality of the proposed primitives, we report performance evaluation results based on a prototype implementation of the password registration protoco

PlexC: A Policy Language for Exposure Control

With the widespread use of online social networks and mobile devices, it is not uncommon for people to continuously broadcast contextual information such as their current location or activity. These technologies present both new opportunities for social engagement and new risks to privacy, and traditional static ‘write once’ disclosure policies are not well suited for controlling aggregate exposure risks in the current technological landscape. Therefore, we present PlexC, a new policy language designed for exposure control. We take advantage of several recent user studies to identify a set of language requirements and features, providing the expressive power to accommodate information sharing in dynamic environments. In our evaluation we show that PlexC can concisely express common policy idioms drawn from survey responses, in addition to more complex information sharing scenarios

An investigation of interoperability issues between authorisation systems within web services

The existing authorisation systems within the context of Web Services mainly apply two access control approaches – Role-Based Access Control (RBAC) and Attribute-Based Access Control (ABAC). The RBAC approach links an authenticated Web Service Requester to its specific access control permission through roles, but RBAC is not flexible enough to cater for some cases where extra attribute information is needed in addition to the identity. By contrast, the ABAC approach has more flexibility, as it allows a Web Service Requester to submit necessary credentials containing extra attribute information that can fulfil the policies declared by a Web Service Provider, which aims to protect the sensitive resources/services.RBAC and ABAC can only help to establish a unilateral trust relationship between two Web Services to enable a Web Service Provider to make an access control decision. Unfortunately, the nature of Web Services presents a high probability that two Web Services may not know each other. Therefore, successful authorisation may fail, if the Web Service Requester does not trust the Web Service Provider.Trust Negotiation (TN) is also an access control approach, which can provide a bilateral trust relationship between two unknown entities, so it sometimes can enable authorisation success in situations where success is not possible through RBAC or ABAC approaches. However, interoperability issues will arise between authorisation systems within Web Services, where a bilateral trust-based authorisation solution is applied. In addition, a lack of a unified approach that can address the interoperability issues remains as a research problem. This research aims to explore possible factors causing the lack of interoperability first, and then to explore an approach that can address the interoperability issues. The main contributions of this research are an improved interoperability model illustrating interoperability issues at different layers of abstraction, and a novel interoperability-solution design along with an improved TN protocol as an example of utilising this design to provide interoperability between authorisation systems within Web Services

An investigation into trust and security in the mandatory and imposed use of financial ICTs upon older people

Care needs to be taken to reduce the number of people who are fearful and mistrustful of using ICT where that usage is forced upon them without choice or alternative. The growing incidence of mandatory and imposed online systems can result in confusion, misuse, fear, and rejection by people with only rudimentary ICT skills. A cohort where a high percentage of such people occur is older people, defined in this study as people over the age of 60 Examples of compulsory ICT interactions include some banks limiting bank statement access through online rather than paper-based options. Other examples include the purchase of theatre or sports events tickets through ticketing systems that require an online transaction to take place. Increasingly, people are living beyond the normal retiring age. As the older cohort increases in size and in overall global population percentage, the problem of forced technology usage affects technology acceptance, technology trust, and technology rejection. People care about ICT systems where reduced trusted acceptance of technology reduces the advantages of digital health care, the perceived security of banking and shopping, and the autonomy of ICT-driven lifestyle choices. This study aims to solve one of the puzzles of ICT-driven change, where older people can show trepidation towards using technology. By understanding the drivers that influence the choices older people make in relation to ICT systems, it may be possible to introduce a much higher level of trusted acceptance in ICT systems. Although many people adopt ICTs into their lives, many older people face difficulty in using technology when it is forced upon them. This study aims to understand the connection between how choice (or lack of choice) can lead to the rejection or resistance towards ICT usage. Older people sometimes opt towards practices that place themselves at risk of financial or informational disadvantage. This study used a qualitative approach to understanding the factors that influenced the trusted acceptance, trepidation, and in some cases rejection of ICT usage by interviewing a sample of older people. Participants were asked to consider a wide range of ICT-usage scenarios and to describe their intentions. The study focussed on circumstances where ICT usage fell under either mandatory, imposed, or voluntary conditions in order to compare user behaviour. Settings included a range of technology-reliant states that examined IT security, volition and choice, aging, trusted acceptance, and technology adoption. Participants were interviewed to discover and sort the conditions (whether singly or in combination) under which the expectation of ICT acceptance was in some way altered, diminished, or prevented. This research found that older people made poor decisions when the choice to use a technology was replaced with a mandatory or strongly imposed pathway. Mandatory ICT usage across the broad area of financial transactions brought about widespread fear and distrust of online technology usage. The results revealed that many older people not only find these innovations daunting and confronting, but they also have difficulty placing their trust in ICT systems and applications that have become mandatory. In normative conditions, increased ICT acceptance and ICT usage is expected. When ICTs are mandatory in their usage, acceptance is replaced with compulsory procedure. This does not mean that mandatory things cannot be accepted, but rather that older people will accept the need to use a technology according to their perception of what is necessary for their daily and routine interactions. This study showed that voluntary ICT usages including choices increase informed decision-making, security of online financial interactions, and trusted reliance upon ICTs. Choice in ICT usage carries greater trust than mandatory, obligated, or heavily imposed ICTs. The study revealed that mandatory ICT systems can create perceptions of fear, mistrust and uncertainty. In situations where a mandatory ICT system becomes the normative method of transaction, a strong risk to the trusted acceptance of a technology is not merely the lack of ICT-based choice, but also the inability to gain reassurance or secondary confirmation through either face to face or telephone-based communication. Trust in not just the usage, but the implied secure usage of mandated and imposed ICTs, is problematic for older people. This study revealed the significance of mandated ICT systems that limit choices for people, because older humans more readily validate and associate their trust in new innovations when they can access various different professional, technical, peer-based, social and popular opinions. The research also showed that older people are fearful and less trusting in mandatory and imposed systems because they have less financial resilience, and less opportunity to bounce back from loss and disadvantage brought about by digital and online interactions. Older people were worried and reluctant to accept technology at first glance because they knew that they had spent more time than others in a pre-internet, pre-digital environment, and their seminal life experiences are correspondingly less technology-related. The results showed that many older people preferred human communication and interaction rather than communicating, buying, paying, and trusting in purely digital, ICT-based experiences. This demonstrated a gap in the trust and security of digital systems, and the need to address those ICTs that impose and mandate instruments and procedures for daily life. Specifically this study looked at what could reduce unsafe and insecure banking practices by understanding the role of choice in the trusted usage of ICT systems. This study is significant because it shows that older people make financial and social, decisions under reactionary, insecure, and under-informed conditions as a result of a gap in terms of trust security and choice. On the one hand older people develop trust towards a new innovation based on accumulated human discussion, information and reputation. On the other hand older people hold the perception that online systems offer reduced choices. This study led to the development of a model for trusted technology choice (TTCM). It differs from traditional acceptance and diffusion thinking, by having outputs as either ICT acceptance or ICT rejection. It diverges from diffusion and technology acceptance models (TAM), because technology acceptance is not regarded as a foregone conclusion. Instead, it places a very high value upon choice and volition, trust, security and human interaction. The TTCM model, together with a framework for identifying volition barriers, provides a different set of criteria for understanding the needs of older people and their meaningful interactions with new innovation and ICTs. The practical applications for using such a model directly impact upon financial and social stability for older people. Where choices are either removed or limited due to ICT usage, older citizens are unfairly disadvantaged. A model that accurately predicts the trusted usage of ICT innovations can have a widespread effect on the implementation of large-scale public and private systems where the trusted acceptance (or rejection) of each system has on flow impact on financial, health, and other critical services that include the growing population of older people