cis3.2 homework #5


  • The homework is due by 8AM on WEDNESDAY DEC 21. You can either email it to me or bring a hardcopy to the final exam.

  • This homework is worth 5 points in total. The distribution of points is indicated below.

  • The homework is a WRITTEN ASSIGNMENT (i.e., no programming) covering internet security topics from the last two lectures.

  • Refer to the notes from Tuesday Nov 29 and Tuesday Dec 6.

  • HINT: completing this assignment will prove very helpful in studying for the final exam!

  • Here is the assignment (5 questions):
    1. (1 point)
      Name one type of passive security threat and one type of active security threat. Briefly explain each type.

    2. (1 point)
      Define and explain the differences between the three categories of computer viruses.

    3. (1 point)
      Encode this message.
      • Given the following plain text input:
      • And given the following encryption algorithm:
        Substitute each letter with the letter that comes n letters after it in alphabetical order, then transpose every pair of letters in the input.
      • And given the following key:
        n = 3
      What is the resulting cypher text?

    4. (1 point)
      What is the difference between a symmetric and an asymmetric encryption system? Give an example of each.

    5. (1 point)
      Name and explain two functions of a firewall.

  • Note that you do not have to submit anything to me by email -- but you can email me your assignment if you won't want to have to print it out. Otherwise, bring a hardcopy of the assignment to the final exam on Wednesday Dec 21 at 8am (in 232NE).