CS 472 Network and Systems Security Fall 2009 Midterm Exam Time 2 & 1/2 hours Open Book & Notes Name: Unix Login: Each Question is 10 points Question 1: The crypto program of assignment #1 is used to encrypt files. The syntax of this program is: % crypto key plainfile cipherfile. Assume you got hold of a cipherfile and find out that the content of the file is all 0s. How you interpret this?