Certifying Program Execution with Secure Processors

Cerium is a trusted computing architecture that protects a program’s execution from being tampered while the program is running. Cerium uses a physically tamperresistant CPU and a μ-kernel to protect programs from each other and from hardware attacks. The μ-kernel partitions programs into separate address spaces, and the CPU applies memory protection to ensure that programs can only use their own data; the CPU traps to the μ-kernel when loading or evicting a cache line, and the μ-kernel cryptographically authenticates and copyprotects each program’s instructions and data when they are stored in the untrusted off-chip DRAM. The Cerium CPU signs certificates that securely identify the CPU and its manufacturer, the BIOS and boot loader, the μ-kernel, the running program, and any data the program wants signed. These certificates tell a user what program executed and what hardware and software environment surrounded the program, which are key facts in deciding whether to trust a program’s output.