Authorization Mechanisms

2. An Access Control Matrix (ACM) is a two-dimensional array that stores access rules for files. Each row represents a user, and each column represents the file under question.
   When some user X wants to access some file Y, the operating system will look into this array and check if user X is allowed to access file Y in the requested way (e.g., read, write, execute, own the file, etc.)
   

   "Table 2-8: Access Control Matrix" (page 79), Pfleeger, Charles P., et al. Security in Computing. Prentice Hall, 2015.