1. March 2005 1R. Smith - University of St Thomas - Minnesota CISC 210 - Class Today Return Homework; grading recapReturn Homework; grading recap “Enigma” – crypto example“Enigma” – crypto example

2. March 2005 2R. Smith - University of St Thomas - Minnesota Homework Grading. Check plus – check – check minus - zeroCheck plus – check – check minus - zero –Basically, means about A-B-C (or zero) –Check Plus = everything right with very minor problems I post the grades on BlackboardI post the grades on Blackboard –Homework grades are CP-CH-CM-or Z If you get extra credit, you might see a number there.If you get extra credit, you might see a number there. Blackboard prints numbers when words aren’t enoughBlackboard prints numbers when words aren’t enough –There should also be a running total of your current grade This can fluctuate wildly if you don’t hand in homeworkThis can fluctuate wildly if you don’t hand in homework Comments on homeworkComments on homework –Handwritten on paper copy –Posted to Blackboard if you only e-mailed your work.

3. March 2005 3R. Smith - University of St Thomas - Minnesota First... ENIGMA But let’s review some questions to askBut let’s review some questions to ask

4. March 2005 4R. Smith - University of St Thomas - Minnesota Bob’s defense of his files Block everyones’ accessBlock everyones’ access Allow his own accessAllow his own access What does the game do?What does the game do?

5. March 2005 5R. Smith - University of St Thomas - Minnesota The attack on Bob Game does the work under Bob’s processGame does the work under Bob’s process

6. March 2005 6R. Smith - University of St Thomas - Minnesota The solution Encrypt the critical dataEncrypt the critical data Policy questionsPolicy questions –What do we encrypt? –When do we encrypt? States of dataStates of data –How do we encrypt? Choice of technologiesChoice of technologies

7. March 2005 7R. Smith - University of St Thomas - Minnesota The Encryption Process Convert plaintext to ciphertext with a keyConvert plaintext to ciphertext with a key

8. March 2005 8R. Smith - University of St Thomas - Minnesota Creative Commons License This work is licensed under the Creative Commons Attribution-Share Alike 3.0 United States License. To view a copy of this license, visit http://creativecommons.org/licenses/by- sa/3.0/us/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA.