Explain computer system architecture

3. bob is arguing that if you use output feedback (ofb) mode twice in a row to encrypt a long message, m, using the same key each time, it will be more secure. explain why bob is wrong, no matter what encryption algorithm he is using for block encryption (15 points).

After you clean an engine with hot water spray, it seems to stall; when it doesn't stall, it's idling noisily. technician a says to check for loose bolts on the flex plate near the torque converter. technician b says to wipe down the spark plug wires and the distributor cap. who is correct? a. technician a b. both technicians a and b c. technician b

Pp 4.1 design and implement a class called sphere that contains instance data that represents the sphere’s diameter. define the sphere constructor to accept and initialize the diameter and include getter and setter methods for the diameter. include methods that calculate and return the volume and surface area of the sphere (see pp 3.5 for the formulas). include a tostring method that returns a one-line description of the sphere. create a driver class called multisphere, whose main method instantiates and updates several sphere objects.