Writing up the design principals of Ethos is one of my goals this summer. The short description is:
(1) Strong security services (authentication, authorization, encryption, isolation)
(2) Higher level, less error prone semantics for all OS interaction.
(3) Security guarantees derived from system layering
(4) Highly composable semantics
Note that only (1) deals with security-specific code. The rest deals with overall code quality.
The research papers are there. There is even a paper reading group. The project appears to be the synthesis of a few "attractive" design choices, combined into one. So each of those things has its own paper(s).
