Puzzle for January 4, 2002

A hypothetical computer science department provides a Hypothetical Computer Science Instructional Facility. Students do their homework on the HCSIF computers. Suppose a student in a beginning programming class writes a program but fails to use the protection mechanisms to prevent others from reading it. A second student reads the first student's program.

  1. If the security policy of the HCSIF says that students are not allowed to read homework-related files from other students, has the second student violated security? Has the first?
  2. If the first student had used the protection mechanisms to prevent other students from reading the file, but the second student figured out a way to read the file, would your answer to part 1 change? If so, how?
  3. If the first student told the second student to "feel free to look at my answer, just don't copy it," would your answer to part 1 change? If so, how?

ECS 153, Introduction to Computer Security
Winter Quarter 2002
Email: cs153@cs.ucdavis.edu