In our domain of expertise, developing software prototypes is mandatory to validate research solutions and is an important vector for research publications, demonstrations at conferences and exhibitions as well as for cooperations with industry. This prototyping task is however difficult because it requires specialized hardware platforms (e.g., smart cards), themselves sometimes at an early stage of development.
Since year 2000, we developed a succession of prototypes addressing different application domains, introducing different technical challenges and relying on different hardware platforms. PicoDBMS was our first attempt to design a full-fledged DBMS embedded in a smart card  . A first prototype was demonstrated at the VLDB'01 conference  and then optimized thanks to a comprehensive benchmarking campaign  conducted on a cycle-accurate hardware simulator. PicoDBMS has been a major vehicle to develop design rules for embedded database components and to set up a long term industrial cooperation with Axalto. Chip-Secured Data Access (C-SDA) embeds a reduced SQL query engine and access right controller in a secure chip and acts as an incorruptible mediator between a client and an untrusted server hosting encrypted data  . Chip-Secured XML Access (C-SXA) is an XML-based access rights controller embedded in a smart card  . C-SXA evaluates user's privileges on a queried or streaming XML encrypted document and delivers the authorized subset of this document. Prototypes of C-SXA have been the recipient of the e-gate open 2004 Silver Award and SIMagine 2005 Gold award, two renowned international software contests. Link: http://www-smis.inria.fr/Eprototypes.html . The next subsections concentrate on the two prototypes focusing our current activity.