International audience`Smart On Smart' (SOS) is a project launched in 2008 and funded by the `Agence Nationale pourla Recherche'. This project aims at helping the partnershipformed by Trusted Logic, Viaccess, LIP6, and the CEA-LETI to study aninnovative secure system architecture. This architecture is based on twoparts. The first one called the host system is in charge of the mainapplication and processes the sensitive data. Connected to the host system thesecond part called the audit system is strictly dedicated to thesecurity strategy response of the whole system.The underlying idea is that such an architecture will help to build abetter secure system. For instance it becomes possible to improve theintelligence of the security policy to be able to differentiate a normalerror behaviour from a suspect one. Since the whole system's securityreliability is adjustable it becomes also possible to maximise theperformance when nonsensitive data are processed. Non repeatablebehaviour and response of the system under attack could be alsoprogrammed in order to counter the attacker.One of the main tasks is to define a hardware architecture correspondingto this concept for which a safe boundary has to be established between thetwo systems. The software part and in particular the way thesecurity policy is implemented on the audit system is also a non obvioustask especially because the overhead due to this additional auditsystem has to be the lowest possible in order to be cost-effective.We are building a proof of concept around a pay TV application. Additionalhardware features are used to emulate fault injection attacks for thedemo. We are building the hardware model on an FPGA board provingalso that such an architecture fits an FPGA based system
