Analyzing SLE 88 memory management security using Interacting State Machines

The Infineon SLE 88 is a smart card processor that offers strong protection mechanisms. One of them is a memory management system typically used for sandboxing application programs dynamically loaded on the chip. High-level (EAL5+) evaluation of the chip requires a formal security model.We formally model the memory management system as an Interacting State Machine and prove, using Isabelle/HOL, that the associated security requirements are met. We demonstrate that our approach enables an adequate level of abstraction, which results in an efficient analysis, and points out potential pitfalls like noninjective address translation.