“unforgeable tokens of authority”
a hardware level execution security measure integrated into every call – called capability systems — or as wikipedia puts it:
“Capability systems can be thought of as a fine-grained sandboxing mechanism, in which programs are given opaque tokens when spawned and have the ability to do specific things based on what tokens they hold”
Intense work done in pure Church-Turing systems in the early 1970s started vanishing during the rise of multics inspired unix grew in the late 1970s, abandoned by 1986, only to be resurrected recently thanks to malware problems. This is a model system from 2019, called CHERI. with “unforgeable tokens of authority”.
Malware + protecting from poor coding leads to a revived interest. HTML rendering in browsers is capability-based user-level sandboxing.