Birla Institute of Technology (BIT Mesra) 2006 NETWORK SECURITY - Question Paper

Birla Institute of Technology & Science, Pilani

Distance Learning Programmes Division

Second Semester 2006-2007



Mid-Semester Test

(EC-1 Regular)



Course No. : SS ZG513

Course Title : NETWORK SECURITY

No. of Pages = 1

No. of ques. = three
Nature of examination : Closed Book

Weightage : 40%

Duration : two Hours

Date of examination : 03/02/2007 (FN)

Note:

1. Please follow all the Instructions to Candidates provided on the cover page of the ans book.

2. All parts of a ques. should be answered consecutively. every ans should begin from a fresh page.

3. Mobile phones and computers of any type should not be brought inside the exam hall.

4. Use of any unfair means will outcome in severe disciplinary action.



Q.1. discuss the DES algorithm with the help of suitable diagram(s). [13]



Q.2. discuss clearly the working of the RSA algorithm. Compare briefly the speeds of RSA and DES. State how security is achieved in RSA. [10 + two + one = 13]



Q.3 (a) explain briefly an efficient algorithm to calculate ax mod n. Show how the algorithm works when a = 51, x = 16, n = 7. [4 + two = 6]



Q.3 (b) Consider the formula ax º one mod n provided a and n (n > 1). State the condition for the formula to have a unique solution modulo n. Solve the formula when a = 55, n = 97. [2 + six = 8]

Earning:   Approval pending.