Completely random selection of possible test questions

All questions used in the past

1.  fc(x) = SE{a,b}	fo(g) = UN{a,b}
    fc(y) = CO{b,c}	fo(h) = CO{c}
    fc(z) = TS{a}	fo(i) = TS{a,b,c}
    fc(v) = UN{}        fo(j) = SE{b,c}

    b-matrix = {(x,i,m),(y,h,o),(v,g,m),(x,j,b)}

    a) Which of the above entries in the b-matrix is definitely illegal?

    b) Write the m-matrix which will make the rest of the entries legal.

2.  Write a Boyer-Moore function which determines whether two items are
    members of a list.
	e.g.  (dmem 8 3 (3 9 4 0)) = F
              (dmem 4 9 (3 9 4 0)) = T

3.  A system has been developed to protect the information of students
    (from disclosure) based on student numbers.  Anybody can see the
    info of the people with the highest numbers, only the actual person
    with the lowest number can see their own info. Write the appropriate
    purge function.

4.  When using the Brewer & Nash Chinese Wall Model, describe a situtation
    where a user could (legally) access a file even though he has seen a
    different file in that same conflict of interest class.

5.  What is the effect of using the first Biba Integrity model along with
    the Bell & Lapadula Model?

6.  Assume that plus is defined as follows:

	(plus a b) = (if (zerop a)
                         b
                         (add1 (plus (sub1 x) y)))

i) Prove that (plus x 0) = x
ii) Prove that (plus i (add1 j)) = (add1 (plus i j))
iii) Use these two facts to prove that (plus x y) = (plus y x)

7.  Describe the purpose & operation of the Kasiski method.

8.  Decrypt the following text:
   
	guvf ceboyrz jnf gbb rnfl sbe n grfg