Strategic Security Intelligence

Interesting Problem Sets

This section is for interesting problem sets that educators may wish to use in their classes. We welcome your submissions. via the list. In the meanwhile, the following assignment may be of interest to some of our readers.

Exercise:

Write a "secure" program to add a finite list of numbers up where "secure" means:

• It always gives the correct answer.
• It only reveals the sum of the numbers as output - and nothing about the list that generated those numbers.
• If it starts running it is guaranteed to complete its task (unless the system crashes) - even if it is operating in a timesharing environment (but one with a fair scheduler and where memory of one program is not overwriten by another program without permission).
• If you need to specify anything else related to this problem, do so and meet that specification with your program..