The Access Matrix
Authorization problems can be represented abstractly by an access matrix.
- each row represents a subject/principal/domain
- each column represents an object
- each cell: accesses permitted for the {subject, object} pair
read, write, delete, execute, search, control, or any other method
In real systems, the access matrix is sparse and dynamic.
We need a flexible and efficient representation, and a model for governing changes to the access matrix.