With the widespread usage of mobile devices and their applications, many areas of innovation have created a multitude of opportunities for mobile technologies to be deployed with very interesting effects. One such new area that emerged in the last few years is mobile commerce. It represents a system where various entities create real–life or digital assets, distribute information about them to interested consumers, execute transactions, accept various types of compensation methods, and finally deliver these assets; all of it in a secure and trusted manner, respecting users’ privacy. Since mobile devices are increasingly used for m-commerce, it is important to ensure that users’ data on such devices are kept secure. Mobile devices contain many of our personal and private data and information, since we nowadays use them for all kind of activities, both personal and professional. However, such data and information are not always treated in a secure and privacy friendly way. The goal of this thesis is to identify and provide solutions to security related problems found on mobile devices, such as communications, storage and mobile application design, and with the use of cryptocurrencies to combine the findings in the design of a secure mobile commerce system. As a result, this thesis describes a design and architecture of a secure e-commerce system, called eAgora, primarily exploiting mobile technology. The system is innovative as it treats digital goods, classified and called mobile commerce objects. Based on the attributes and anticipated use of such specific m–commerce objects, different security and privacy measures for each of them are needed and enforced. The goal was to design a system that deals with mobile commerce in a secure and privacy friendly way in all the lifecycle of the transactions. As users are mostly using mobile devices to connect to the proposed services, research first focused on mobile device security and privacy issues, such as insecure storage on the mobile device, insecure handling of user credentials and personal information, and insecure communications. Issues not only coming from the device itself but also from the nature of it; being mobile it is used in a different way that the classical desktop computers. Mobile devices are used in public, in an environment that cannot be controlled, and are interfacing a variety of networks that are not under the mobile device user’s control. Potential attackers’ interest was analysed in different mobile commerce scenarios in order to understand the needs for security enhancements. After having analyzed the possible threats, a methodology for mobile application development that would allow many common development errors to be avoided and security and privacy mechanisms to be considered by design was specified. Moreover, in order to provide secure storage and guard against active and passive intruder attacks, a secure Mobile Crypto Services Provider facility that allows storage of data on the UICC cards was designed and implemented. In order to secure communications, a secure e-mail application was designed and implemented. The application provides a user-friendly way to encrypt and sign e-mails, using the users’ already working e-mail accounts. The security functionality is completely transparent to users and ensures confidentiality and integrity of e-mail exchange. For the mobile commerce system, an architecture that enables exchange of m-commerce objects between different merchants, customers and retailers is proposed. Inthe architecture, policy enforcement and the feature to detect suspicious events that may be illegal and to cooperate with law enforcement was embedded. The newly defined technology of virtual currencies is used as a payment facilitator within the proposed architecture. Many of its innovative features are adopted but some are also extended, such as the secure use of the user wallet files, i.e. the files that link the user with the virtual currencies and enable payment transactions between customers and merchants. Although there is no distinction between different virtual currencies, Bitcoin is used as an example of a market valued trading currency to validate and evaluate the proposed secure e-commerce architecture and the findings have been applied on it. The thesis provides detailed use cases that demonstrate how the proposed architecture of eAgora functions in different complicated e-trading circumstances and how different security related mechanisms are used. The thesis concludes with the analysis of the research results and with proposed directions for future research and development works. / <p>QC 20150521</p>