Take-grant protection model

The take-grant protection model is a formal model used in the field of computer security to establish or disprove the safety of a given computer system that follows specific rules. It shows that for specific systems the question of safety is decidable in linear time, which is in general undecidable. The model represents a system as directed graph, where vertices are either subjects or objects. The edges between them are labeled and the label indicates the rights that the source of the edge has over the destination. Two rights occur in every instance of the model: "take" and "grant". They play a special role in the graph rewriting rules describing admissible changes of the graph.

There is a total of four such rules: The "take rule" allows a subject to take rights of another subject, while the "grant rule" allows a subject to grant own rights to another subject. The "create rule" allows every subject to create new nodes, while the "remove rule" allows a subject to remove rights it has over another object.

Using the rules of the take-grant protection model, one can reproduce in which states a system can change, with respect to the distribution of rights. Therefore one can show if rights can leak with respect to a given safety model.

References

* cite journal
author = Lipton, Richard J.
coauthors = Snyder, Lawrence
title = A Linear Time Algorithm for Deciding Subject Security
journal = Journal of the ACM
volume = 24
issue = 3
pages = 455–464
date = 1977
publisher = Addison-Wesley
url = http://www.cs.nmt.edu/~doshin/t/s06/cs589/pub/2.JLS-TG.pdf
format = PDF
* cite book
last = Bishop | first = Matt
title = Computer security: art and science
publisher = Addison-Wesley
year = 2004