The US Defense Advanced Research Projects Administration (DARPA) and Australia’s National Information and Communication Technology Agency (NICTA) have released the code for the ultra-secure embedded microkernel operating system that is used with flying drone devices. The seL4 (Secure L4) system is based on the L4 microkernel. The kernel is available for download at the seL4 system website.
L4 is a microkernel system used in mobile devices throughout the world. A microkernel design implements a modular architecture, minimizing the size of the kernel itself and maximizing the number of services that are able to run in userspace. The modular design and minimal use of code in kernel space means microkernel systems are (at least theoretically) more stable and more secure. Famous microkernels include Minix (which influenced the early development of Linux) and GNU Herd. The L3 and L4 systems were originally developed by German computer scientist Jochen Liedtke, who wanted to build a microkernel that was free of the performance issues associated with previous attempts. Researchers at NICTA joined with DARPA and aviation industry experts to develop seL4 from the L4 microkernel.
The seL4 system came from the need to create a microkernel that could be used in aerial drones and would be completely and verifiably free from the possibility of attack. The code for the kernel has undergone formal verification, a mathematical proof that the algorithms used in the system will perform as specified and won't be subject to intrusion.
Now that the highly stable and secure seL4 is in open source, other vendors will probably start to consider it for other mission critical embedded systems, such as medical implants and navigation devices.