Machine-readable media, methods, apparatus and system for booting a processing system are described. In an embodiment, whether to launch an open operating system or a closed operating system to boot a processing system may be determined. A key may be retrieved from a processor register of the processing system and used to decrypt an encrypted version of the closed operating system based at least in part on a determination of booting the processing system with the closed operating system. In another embodiment, the processor register stored with the key may be flushed based at least in part on a determination of booting the processing system with the open operating system.