Announcing Xous: the Betrusted Operating System

Today we’re pleased to announce the Betrusted project. The goals of this project are to create a secure platform that is auditable by the end user, and is capable of performing secure communications. Betrusted is a tethered communications platform, not a standalone phone.

Joining me on this project are Bunnie and Tom Marble, who will be primarily working on the hardware and software layers of the stack respectively.

My role in this is to develop the operating system layer, dubbed Xous. This operating system will be a microkernel architecture in order to enforce separation between services running on the device. To further enhance safety, this kernel will be written in Rust, and interprocess communication will follow Rust borrowing rules when sharing memory.

This will be particularly challenging because a design goal of Betrusted is to limit the amount of memory on the system. In doing so, we naturally limit the number of features we can implement, which will reduce attack surface.

Xous will require an MMU, which is somewhat unusual in embedded systems - an MPU is much more common in small devices. Thanks to our use of the amazing VexRisc cpu core, adding an MPU is as easy as adding a flag and rebuilding the output Verilog.

The coming year will see exciting developments within the Betrusted hardware and software stacks. I’ll post more information once we have more progress.

The Betrusted project, including the Xous operating system, are made possible thanks to financial assistance from NLNet and the NG10 Privacy & Trust Enhancing Technologies Fund. Thank you to them for their support.