The Typed Access Matrix Model TAM and Augmented

The Typed Access Matrix Model (TAM) and Augmented TAM (ATAM) Ravi Sandhu Laboratory for Information Security Technology George Mason University www. list. gmu. edu sandhu@gmu. edu © 2004 Ravi Sandhu www. list. gmu. edu

Outline • TAM: Typed Access Matrix Model • TAM adds types to HRU and preserves strong safety results of SPM/ESPM • SO-TAM: Single Object TAM • SO-TAM manipulates one column of the access matrix at a time and is equivalent to TAM • ATAM: Augmented TAM • ATAM adds testing for absence of rights to TAM • ATAM is equivalent to TAM in one sense but more expressive in another © 2004 Ravi Sandhu www. list. gmu. edu 2

TAM adds types to HRU © 2004 Ravi Sandhu www. list. gmu. edu 3

TAM adds types to HRU © 2004 Ravi Sandhu www. list. gmu. edu 4

TAM commands © 2004 Ravi Sandhu www. list. gmu. edu 5

TAM primitive operations © 2004 Ravi Sandhu www. list. gmu. edu 6

TAM operations: enter and delete © 2004 Ravi Sandhu www. list. gmu. edu 7

TAM operations: create and destroy © 2004 Ravi Sandhu www. list. gmu. edu 8

TAM operations: create and destroy © 2004 Ravi Sandhu www. list. gmu. edu 9

ORCON in TAM © 2004 Ravi Sandhu www. list. gmu. edu 10

ORCON in TAM © 2004 Ravi Sandhu www. list. gmu. edu 11

ORCON in TAM © 2004 Ravi Sandhu www. list. gmu. edu 12

ORCON in TAM © 2004 Ravi Sandhu www. list. gmu. edu 13

MTAM: Monotonic TAM © 2004 Ravi Sandhu www. list. gmu. edu 14

MTAM Canonical Schemes © 2004 Ravi Sandhu www. list. gmu. edu 15

MTAM Canonical Schemes © 2004 Ravi Sandhu www. list. gmu. edu 16

ORCON as a MTAM Canonical Scheme © 2004 Ravi Sandhu www. list. gmu. edu 17

Acyclic TAM schemes © 2004 Ravi Sandhu www. list. gmu. edu 18

Acyclic TAM unfolded state © 2004 Ravi Sandhu www. list. gmu. edu 19

Acyclic MTAM unfolded state © 2004 Ravi Sandhu www. list. gmu. edu 20

Acyclic MTAM safety © 2004 Ravi Sandhu www. list. gmu. edu 21

Ternary MTAM © 2004 Ravi Sandhu www. list. gmu. edu 22

Ternary MTAM © 2004 Ravi Sandhu www. list. gmu. edu 23

Binary and Unary MTAM • Useless • Binary MTAM • Single-parent creation or spontaneous doublechild creation • Less expressive than multi-parent creation © 2004 Ravi Sandhu www. list. gmu. edu 24

SOTAM: single object TAM © 2004 Ravi Sandhu www. list. gmu. edu 25

SOTAM • SOTAM is equivalent in expressive power to TAM © 2004 Ravi Sandhu www. list. gmu. edu 26

ATAM: Augmented TAM • Allow testing for absence of rights in the conditions of commands • ATAM is equivalent in expressive power to TAM in unbounded simulation but most likely not in bounded simulation • “Most likely not” has recently been shown to be “provably cannot” © 2004 Ravi Sandhu www. list. gmu. edu 27