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

Saturday, 19 January 2013 09:25Web

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 pag

**e.**

**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 RS

**A.**[10 + two + one = 13]

**Q.3**

**(**explain briefly an efficient algorithm to calculate ax mod n. Show how the algorithm works when a = 51, x = 16, n =

**a)****7.**[4 + two = 6]

**Q.3**

**(**Consider the formula ax ยบ 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 =

**b)****9**[2 + six = 8]

**7.**Earning: Approval pending. |