Multi-Level Security was developed in the 1970s after there were problems with air traffic control/flight plan data processing issues related to security classification levels during the Viet-Nam war.
Operating Systems that supported Capabilities such as GNOSIS were in operation in the 1970s. Multics was planned to add Capability Object support.
Unix short-circuited history, and for the most part, Capabilities were forgotten, because they were seen as unnecessary and wasteful of resource.
I believe it is time to re-examine these beliefs, and start a push towards widely deploying Multi Level Secure systems.
References:
https://en.wikipedia.org/wiki/Multilevel_security https://en.wikipedia.org/wiki/Bell%E2%80%93LaPadula_model https://en.wikipedia.org/wiki/KeyKOS https://en.wikipedia.org/wiki/Genode http://cap-lore.com/CapTheory/KK/
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