We gratefully acknowledge feedback and support from our colleagues including John Baldwin, Kevin Brodsky, Brooks Davis, and Laurence Tratt.

This work was supported by Innovate UK project "Digital Security by Design (DSbD) Technology Platform Prototype", 105694.

Approved for public release; distribution is unlimited. Sponsored by the Defense Advanced Research Projects Agency (DARPA) under contract HR0011-22-C-0110 ("ETC"). The views, opinions, and/or findings contained in this report are those of the authors and should not be interpreted as representing the official views or policies, either expressed or implied, of the Department of Defense or the U.S. Government.

We gratefully acknowledge UK Research and Innovation (UKRI), who sponsored the creation of Morello, and the significant investment by DARPA in supporting the creation of CHERI and its earlier prototypes. We also acknowledge Arm Limited and Google, Inc.