Formal Models of Capability-Based Protection Systems

TLDR

Capability‑based protection systems have a long history, illustrated by a model of a computer science department’s computer system. The paper explains the role of formal modeling in studying capability‑based protection systems. It surveys key models—including Harrison–Ruzzo–Ullman, Take‑Grant, and grammatical models—and presents them in a unified framework with consistent terminology. The study presents the main results of these models, comparing and contrasting them through numerous examples.

Abstract

The role of formal modeling in the study of capability- based protection systems is explained. Historical background is presented and a model of a computer science department's computer system is presented. A survey of several important capability-based models is given including the Harrison, Ruzzo, Ullman model, the Take-Grant model, and grammatical models. These models are presented in a unified manner with consistent terminology. The main results of the models are given. These results are compared, contrasted, and interpreted in the context of numerous examples.