Dynamic resource security

What is a history/resource trace?

A list where the elements of the set are thought of as resource events

What is a sigma property?

a set of histories

what is an event?

actions of a subject on an object

do authorization and availability have to be subject specific?

true

what is the type of the value of a permission matrix element M

set of actions

what is denoted by B in the AC model?

access matrix

what is the clearance constraint for a subject u?

pl(u) < or = cl(u)

which of the following are histories if a and b are events?

() {} (a) (a:b::a::b)

() (a) (a:b::a::b)

which of the following are properties, if a and b are events?

() {} {a} {a,b}

{} {a} {a,b}

in which of the following is x a prefix of y?

x = aba y =ab

x = a y = aab

x = a y = b

x = ba y = abba

x = a y = aab

if a b and c are events which of the following traces are in the set a bar (set of all traces where the event a occurs in the trace)?

(aaba)

(bbbb)

(cbcb)

(ccca)

(aaba) (ccca)