Abstract. The Java Card uses two components to ensure the security of its model. On the one hand, the byte code verifier (BCV) checks, during an applet installation, if the Java Card security model is ensured. This mechanism may not be present in the card. On the other hand, the firewall dynamically checks if there is no illegal access. This paper describes two attacks to modify the Java Card control flow and to execute our own malicious byte code. In the first attack, we use a card without embedded security verifier and we show how it is simple to change the return address of a current function. In the second attack, we consider the hypothesis that the card embeds a partial implementation of a BCV. With the help of a laser beam, we are able to change the execution flow.

This paper presents a method to inject a mutable Java Card applet into a smart card. This code can on demand parse the memory in order to search for a given pattern and eliminate it. One of these key features is to bypass security checks or retrieve secret data from other applets. We evaluate the countermeasures against this attack and we show how some of them can be circumvented and we propose to combine this attack with others already known.

No abstract

No abstract

This paper presents a fail-safe platform on which cooperative mobile robots rely for their motion. The platform consists of a collision prevention protocol for a dynamic group of cooperative mobile robots with asynchronous communications. The collision prevention protocol is timefree, in the sense that it never relies on physical time, which makes it extremely robust for timing uncertainty common in wireless networks. It guarantees that no two robots ever collide, regardless of the respective activities of the robots. The protocol is based on a fully distributed path reservation system. It assumes a mobile ad hoc network formed by the robots themselves, and takes advantage of the inherent locality of the problem in order to reduce communication. The protocol requires neither initial nor complete knowledge of the composition of the group. A performance analysis of the protocol provides insights for a proper dimensioning of system parameters in order to maximize the average effective speed of the robots.