Code No: R41051
R10
Set No. 1
IV B.Tech I Semester Regular Examinations, December - 2013
CRYPTOGRAPHY AND NETWORK SECURITY
(Common to Computer Science & Engineering and Information Technology)
Time : 3 hours
Max. Marks: 75
1 a)
b)
Answer any Five Questions
All Questions carry equal marks
**
Explain various security services in detail.
Explain rail fence transposition technique.
[8]
[7]
2 a)
b)
Explain Feistel encryption structure with diagram.
Explain the triple DES in detail.
[8]
[7]
3 a)
b)
State and prove Chinese Remainder Theorem.
Define a primitive root. Find all primitive roots of 25.
[8]
[7]
4 a)
b)
Explain public key encryption scheme.
Perform encryption and decryption using RSA algorithm for p=3,q=11,e=7
and M=5.
[8]
[7]
5 a)
b)
What are the requirements of a Hash function.
Explain SHA-1 algorithm.
[8]
[7]
6 a)
b)
With the help of neat diagram, explain Kerberos action.
Explain the following PGP services.
i) Authentication
ii) Confidentiality
[8]
[7]
7 a)
b)
Explain secure electronic commerce components in detail.
Explain benefits of IPSec.
[8]
[7]
8 a)
Briefly explain the following:
i) Trapdoors
ii) logic bomb
iii) Trojan horse
Explain the concept of trusted systems.
[8]
b)
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iv) Viruses
[7]
Code No: R41051
R10
Set No. 2
IV B.Tech I Semester Regular Examinations, December - 2013
CRYPTOGRAPHY AND NETWORK SECURITY
(Common to Computer Science & Engineering and Information Technology)
Time : 3 hours
Max. Marks: 75
1 a)
b)
Answer any Five Questions
All Questions carry equal marks
**
Explain various kinds of security mechanisms in detail.
Explain monoalphabetic cipher in detail.
[8]
[7]
2 a)
b)
Explain the DES encryption algorithm.
Explain the strength of the DES.
[8]
[7]
3 a)
b)
Define Euler’s Totient function. Determine ¢(37) and ¢(35).
Use Fermat’s theorem to find a number x between 0 and 28 with x85
congruent to 6 modulo 35.
[8]
[7]
4 a)
b)
Explain public key cryptosystem for secrecy and authentication.
Explain Deffie-Hellman key exchange.
[8]
[7]
5 a)
b)
Explain MD5 in detail.
Explain Simple Hash Function.
[8]
[7]
6 a)
b)
Explain X.509 Authentication Services.
Describe S/MIME.
[8]
[7]
7 a)
b)
Explain the SSL Record Protocol.
Explain Web Security threats.
[8]
[7]
8 a)
b)
Explain password selection procedure in detail.
Explain the capabilities and limitations of firewalls.
[8]
[7]
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Code No: R41051
R10
Set No. 3
IV B.Tech I Semester Regular Examinations, December - 2013
CRYPTOGRAPHY AND NETWORK SECURITY
(Common to Computer Science & Engineering and Information Technology)
Time : 3 hours
Max. Marks: 75
1 a)
b)
Answer any Five Questions
All Questions carry equal marks
**
Explain the symmetric key encryption model.
Explain Caesar Cipher in detail.
[8]
[7]
2 a)
b)
Explain block cipher design principles in detail.
Explain single round of DES.
[8]
[7]
3 a)
b)
State and prove Euler’s theorem.
Use Euler’s theorem to find a number a between 0 and 9 such that a is
congruent to 71000 modulo 10.
[8]
[7]
4 a)
b)
What are the principal elements of a public key cryptosystem? Explain.
In a public key system using RSA, you intercept the cipher text C=10 sent to
a user whose public key is e=5, n= 35. What is the plain text M?
[8]
[7]
5 a)
b)
What is a MAC? Explain message authentication using MAC.
Explain RIPEMD-160 in detail.
[8]
[7]
6 a)
b)
Explain Kerberos version 4 message exchange.
Briefly explain the PGP services.
[8]
[7]
7 a)
b)
Describe IP Security.
Explain IPSec ESP format.
[8]
[7]
8 a)
b)
Explain various approaches to Intrusion Detection.
What is a firewall? Explain packet filter router.
[8]
[7]
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Code No: R41051
R10
Set No. 4
IV B.Tech I Semester Regular Examinations, December - 2013
CRYPTOGRAPHY AND NETWORK SECURITY
(Common to Computer Science & Engineering and Information Technology)
Time : 3 hours
Max. Marks: 75
1 a)
b)
Answer any Five Questions
All Questions carry equal marks
**
Explain various security attacks in detail.
Explain the model of conventional crypto system.
[8]
[7]
2 a)
b)
Explain block cipher modes of operations.
Explain CAST-128 cipher.
[8]
[7]
3 a)
b)
State and Prove Fermat’s theorem.
Use Fermat’s theorem to find a number x between 0 and 28 with x85
congruent to 6 modulo 29.
[8]
[7]
4 a)
b)
Explain RSA algorithm in detail.
Perform encryption and decryption using RSA algorithm for p=5,q=11,e=3
and M=9.
[8]
[7]
5 a)
b)
Compare the principal characteristics of MD5,SHA-1,and RIPEMD-160.
What is a digital signature? Explain this using public key algorithm.
[8]
[7]
6 a)
b)
What is Kerberos? What are the requirements of a Kerberos?
Explain the limitations of SMTP/822 scheme.
[8]
[7]
7 a)
b)
Explain the IPSec Authentication Header fields with diagram.
Explain the payment process supported in SET.
[8]
[7]
8 a)
b)
Describe different classes of Intruders.
Explain malicious programs.
[8]
[7]
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