SecBus, a Software/Hardware Architecture for Securing External Memories

Embedded systems are ubiquitous nowadays. In many cases, they manipulate sensitive applications or data and may be the target of logical or physical attacks. On systems that contain a System-on-Chip connected to an external memory, which is the case of numerous medium to large-size embedded systems, the content of this memory is relatively easy to retrieve or modify. This attack can be performed by probing the memory bus, dumping the content of the memory (cold boot attack) or by exploiting flaws in DMA-capable devices. Thus, if the embedded system manipulates sensitive applications or data, the confidentiality and the integrity of data in memory shall be protected. SecBus is a combined hardware/software architecture that guarantees these two security properties. This paper describes the different software components that are in charge of the management of the SecBus platform, from the early initialization to their use by the sensitive applications.