1. What is the difference between authentication and authorization? Authorization is usually explained using the ___________________ model.

2. Let O be a set of ____________ (assets). Let S be a set of _______ (users. processes, network nodes, packets, etc.). Let R be a set of possible ____________. An access matrix A is a function O  S   R Example S = {Ole, Lena} O = {OleFile, LenaFile, SharedFile} R = {read, write} A = { read, write } Ø { read } OleFileLenaFileSharedFile Lena Ole In this model a set of protection states is represented by a triple, (S, O, A)

3. gates_wh obama_bh www.fed.govwww.dribble.com Remote Server Access

4. Access to the Members of a Java Class public class Arg { public int fee; private int fi; public void foo() { int fo; int fum; // code missing } public void foo2() { int fo; int fi; // code missing }

5. The same right may mean something different in another context or another system. Example: What does an execute permission mean on a Unix directory? What are typical elements of a set of rights? Special Rights ______ -- most assets have one signified owner. ______ -- A subject with copy permission can grant permissions to other subjects.

6. Changing protection states is an integral part of computation. Potential Changes  create a new subject (S, O, A)(S', O', A') S' = S  {newSubject} and add row for newSubject to A using Ø for new rights  destroy a subject S' = S - {someSubject} and remove someSubject row from A  create a new asset O' = O  {newAsset} and add column for newAsset to A using Ø for new rights  destroy an asset O' = O - {someAsset} and remove someAsset column from A  add a new right (  a'[s,o]  A') [ a'[s,o] = a[s,o]  {newRight} ] and nothing else changes  remove a right (  a'[s,o]  A') [ a'[s,o] = a[s,o] - {someRight} ] and nothing else changes

7. { read, write, own }{ read, write } Ø{ read, own }{ write } { read }{ write, own } { read } { read, write } OleFileLenaFileSharedFile Lena Ole Bubba Daisy A capability is a row of the ACM. An access control list (ACL) is a column of the ACM. ACLs often incorporate group permissions, as well as individual. Vulnerability -- Basing access on subjects allows for “ impersonation. ”