An increasing amount of personal data is automatically gathered on servers by administrations, hospitals and private companies while several security surveys highlight the failure of database servers to keep confidential data really private. The advent of powerful secure tokens, combining the security of smart card microcontrollers with the storage capacity of NAND Flash chips, introduces a credible alternative to the systematic centralization of personal data. By embedding a full-fledged database server in such device, an individual can now store her personal data in her own secure token, kept under her control, and never disclose in clear her private data to the outside untrusted world. This demonstration shows the benefit of the proposed approach in terms of privacy protection and pervasiveness through a healthcare scenario. This scenario is extracted from a field experiment where medical folders embedded in secure tokens are used to improve the coordination of medical care at home for elderly people. The demonstration also highlights interesting features of the embedded DBMS engine introduced to tackle the secure token's strong hardware constraints.

This article presents a new way to deploy and customize embedded virtual machine based operating systems for very restrained devices. Due to the specificity of restrained embedded devices (large usage of read-only memory, very few writable memory available, …), these systems are typically deployed off-board, in a process called romization . However, current romization solutions do not allow a complete deployment to take place outside of the execution device: they are capable of converting system components and applications into their executable form, but are unable to perform any operation that would require the system to be running. This results in a good part of the deployment being performed by the target device, at the cost of longer startup times, bloat with code and data that are only executed once at startup, and suboptimal memory placement of data structures. In this article, we propose a new romization scheme that allows the system to be started within a virtual execution environment, and thus to be fully deployed off-board before being transferred to its real execution support. We then take advantage of all the information provided by the deployed state in order to analyze and customize it, resulting in a very low-footprint, custom-tailored embedded system. The Java platform is used as a support to implement our romization architecture and perform our experiments. For the evaluated set of embedded applications, we were able to obtain embedded systems which memory footprint was lower than their J2ME counterpart, while being based on a full-fledged J2SE environment.

In this paper, we show that Web protocols and technologies are good candidates to design the Internet of Things, through a user-centric architecture (the user simply has to use a standard Web browser). We detail how this Web of Things can handle typical embedded devices interaction needs. We discuss the technical feasibility of embedded Web servers, and, thanks to an analysis of the Web protocols, we propose new cross-layer solutions for efficient tiny embedded Web servers design. The problem of event notification for Web applications is also discussed. We finally present a prototype - named Smews - as a proof of concept of the Web of Things. Smews implements our proposals and has been embedded in tiny devices (smart cards, sensors and other embedded devices), with a requirement of only 200 bytes of volatile memory and 7 kilo-bytes of code. We show that it is significantly faster than other state of the art solutions. We made Smews source code publically available under an open-source license.

Embedded systems such as smart cards or sensors are now widespread, but are often closed systems, only accessed via dedicated terminals. A new trend consists in embedding Web servers in small devices, making both access and application development easier. In this paper, we propose a TCP performance model in the context of embedded Web servers, and we introduce a taxonomy of the contents possibly served by Web applications. The main idea of this paper is to adapt the communication stack behavior to application contents properties. We propose a strategies set fitting with each type of content. The model allows to evaluate the benefits of our strategies in terms of time and memory charge. By implementing a real use case on a smart card, we measure the benefits of our proposals and validate our model. Our prototype, called Smews, makes a gap with state of the art solutions both in terms of performance and memory charge.