DAA-TZ: An Efficient DAA Scheme for Mobile Devices using ARM TrustZone

Direct Anonymous Attestation (DAA) has been studied for applying to mobile devices based on ARM TrustZone. However, current solutions bring in extra performance overheads and security risks when adapting existing DAA schemes originally designed for PC platform. In this paper, we propose a complete and efficient DAA scheme (DAA-TZ) specifically designed for mobile devices using TrustZone. By considering the application scenarios, DAA-TZ extends the interactive model of original DAA and provides anonymity for a device and its user against remote service providers. The proposed scheme requires only one-time switch of TrustZone for signing phase and elaborately takes pre-computation into account. Consequently, the frequent on-line signing just needs at most three exponentiations on elliptic curve. Moreover, we present the architecture for trusted mobile devices. The issues about key derivation and sensitive data management relying on a root of trust from SRAM Physical Unclonable Function (PUF) are discussed. We implement a prototype system and execute DAA-TZ using MNT and BN curves with different security levels. The comparison result and performance evaluation indicate that our scheme meets the demanding requirement of mobile users in respects of both security and efficiency

AEP-M: Practical Anonymous E-Payment for Mobile Devices using ARM TrustZone and Divisible E-Cash (Full Version)

Electronic payment (e-payment) has been widely applied to electronic commerce and has especially attracted a large number of mobile users. However, current solutions often focus on protecting users\u27 money security without concerning the issue of users\u27 privacy leakage. In this paper, we propose AEP-M, a practical anonymous e-payment scheme specifically designed for mobile devices using TrustZone. On account of the limited resources on mobile devices and time constraints of electronic transactions, we construct our scheme based on efficient divisible e-cash system. Precisely, AEP-M allows users to withdraw a large coin of value $2^{n}$ at once, and then spend it in several times by dividing it without revealing users\u27 identities to others, including banks and merchants. Users\u27 payments cannot be linked either. AEP-M utilizes bit-decomposition technique and pre-computation to further increase the flexibility and efficiency of spending phase for mobile users. As a consequence, the frequent online spending process just needs at most $n$ exponentiations on elliptic curve on mobile devices. Moreover, we elaborately adapt AEP-M to TrustZone architecture for the sake of protecting users\u27 money and critical data. The methods about key derivation and sensitive data management relying on a root of trust from SRAM Physical Unclonable Function (PUF) are presented. We implement a prototype system and evaluate AEP-M using Barreto-Naehrig (BN) curve with 128-bit security level. The security analysis and experimental results indicate that our scheme could meet the practical requirement of mobile users in respects of security and efficiency

DOT-M: A Dual Offline Transaction Scheme of Central Bank Digital Currency for Trusted Mobile Devices

In recent years, many major economies have paid close attention to central bank digital currency (CBDC). As an optional attribute of CBDC, dual offline transaction is considered to have great practical value under the circumstances for payment without network connection. However, there is no public report or paper on how to securely design or implement the dual offline transaction function specifically for CBDC. In this paper, we propose DOT-M, a practical dual offline transaction scheme designed for the mobile device user as either a payer or a payee. Precisely, adopting secure element (SE) and trusted execution environment (TEE), the architecture of trusted mobile device is constructed to protect security-sensitive keys and execution of the transaction protocol. According to the trusted architecture, the data structure for offline transaction is designed as well. On this basis, we describe the core procedures of DOT-M in detail, including registration, account synchronization, dual offline transaction, and online data updating. We also enumerate the exceptional situations that may occur during the dual offline transaction, and give specific handling methods for each situation. Moreover, six security properties of the scheme are analyzed under realistic assumptions. A prototype system is implemented and finally tested with possible parameters. The security analysis and experimental results indicate that our scheme could meet the practical requirement of CBDC offline transaction for mobile users from both aspects of security and efficiency

Security, Trust and Privacy (STP) Model for Federated Identity and Access Management (FIAM) Systems

The federated identity and access management systems facilitate the home domain organization users to access multiple resources (services) in the foreign domain organization by web single sign-on facility. In federated environment the user’s authentication is performed in the beginning of an authentication session and allowed to access multiple resources (services) until the current session is active. In current federated identity and access management systems the main security concerns are: (1) In home domain organization machine platforms bidirectional integrity measurement is not exist, (2) Integrated authentication (i.e., username/password and home domain machine platforms mutual attestation) is not present and (3) The resource (service) authorization in the foreign domain organization is not via the home domain machine platforms bidirectional attestation

Securing Critical Infrastructures

1noL'abstract è presente nell'allegato / the abstract is in the attachmentopen677. INGEGNERIA INFORMATInoopenCarelli, Albert

Design and Analysis of Fair Content Tracing Protocols

The work in this thesis examines protocols designed to address the issues of tracing illegal distribution of digital content in a fair manner. In digital content distribution, a client requests content from a distributor, and the distributor sends content to the client. The main concern is misuse of content by the client, such as illegal distribution. As a result, digital watermarking schemes that enable the distributor to trace copies of content and identify the perpetrator were proposed. However, such schemes do not provide a mechanism for the distributor to prove to a third party that a client illegally distributed copies of content. Furthermore, it is possible that the distributor falsely accuses a client as he has total control of the tracing mechanisms. Fair content tracing (FaCT) protocols were thus proposed to allow tracing of content that does not discriminate either the distributor or the client. Many FaCT protocols have been proposed, mostly without an appropriate design framework, and so there is no obvious and systematic way to evaluate them. Therefore, we propose a framework that provides a definition of security and which enables classification of FaCT protocols so that they can be analysed in a systematic manner. We define, based on our framework, four main categories of FaCT protocols and propose new approaches to designing them. The first category is protocols without trusted third parties. As the name suggests, these protocols do not rely on a central trusted party for fair tracing of content. It is difficult to design such a protocol without drawing on extra measures that increase communication and computation costs. We show this is the case by demonstrating flaws in two recent proposals. We also illustrate a possible repair based on relaxing the assumption of trust on the distributor. The second category is protocols with online trusted third parties, where a central online trusted party is deployed. This means a trusted party must always be available during content distribution between the distributor and the client. While the availability of a trusted third party may simplify the design of such protocols, efficiency may suffer due to the need to communicate with this third party. The third category is protocols with offline trusted third parties, where a central offline trusted party is deployed. The difference between the offline and the online trusted party is that the offline trusted party need not be available during content distribution. It only needs to be available during the initial setup and when there is a dispute between the distributor and the client. This reduces the communication requirements compared to using an online trusted party. Using a symmetric-based cryptographic primitive known as Chameleon encryption, we proposed a new approach to designing such protocols. The fourth category is protocols with trusted hardware. Previous protocols proposed in this category have abstracted away from a practical choice of the underlying trusted hardware. We propose new protocols based on a Trusted Platform Module (TPM). Finally, we examine the inclusion of payment in a FaCT protocol, and how adding payment motivates the requirement for fair exchange of buying and selling digital content

Building the Infrastructure for Cloud Security

Computer scienc

Advancing Dietetic Practice through the Implementation and Integration of Smartphone Apps

As the burden of obesity and its related chronic diseases grows, dietitians have integral roles in providing individualised medical nutrition therapy. Smartphone mobile health (mHealth) applications (apps) have potential to support and extend reach of dietetic services. This thesis examines how mHealth apps could be implemented and integrated by dietitians to advance nutrition care. Based on a narrative review of current evidence, the novel mobile Nutrition Care Process grid was developed, providing dietitians with best-practice guidance for using mHealth apps across the nutrition care process. Surveying dietitians internationally revealed that 62% used mHealth apps in their practice, although primarily as an information resource and for patient self-monitoring rather than as an integral part of the nutrition care process. Similarly, the public used commercial health and fitness apps, such as MyFitnessPal, to track health behaviours. However, individuals performed suboptimally when using MyFitnessPal to track dietary intake, with the app underestimating mean energy intake by -1863kJ (SD=2952kJ, P=0.0002) compared to 24-hour recalls. Qualitative feedback from dietitians, the public and patients are presented to guide app developers in designing quality mHealth apps. A behavioural analysis was conducted using the COM-B model and intervention recommendations were formulated to facilitate uptake of mHealth apps into dietetic practice. These recommendations were incorporated into a two-phase intervention comprising of an educational and training workshop and a 12-week phase where dietitians used an integrated commercial app platform with their patients. The intervention was found to be feasible to deliver and improved dietitians’ mHealth app self-efficacy. There is translational potential for this intervention to equip the profession with greater capability, opportunity, motivation and self-efficacy to use mHealth apps in dietetic practice and in patient nutrition care