Gujarat Power Engineering and Research Institute
1
INFORMATION SECURITY
SUBJECT CODE: 160702
B.E. 6th SEM (COMPUTER ENGINEERING)
ASSIGNMENT-1
(1)Define the terms threat and attack. List and briefly define
categories of security
attacks.
(2)List and briefly define the security services.
(3)What is cryptography? Write the differences between
conventional encryption
and public key encryption.
(4) Define following terms:
a. Cryptanalyst
b. Cryptanalysis.
(5) Explain the various types of cryptanalytic attack, based on
the amount of
information known to the cryptanalyst. (or What is the objective
of attacking an
encryption system? Write the possible approaches to attack a
conventional
encryption scheme.)
(6)Explain monoalphabetic cipher and polyalphabetic cipher by
giving an Example
(7)Define the Caesar cipher.
(8) Is playfair cipher monoalphabetic cipher? Justify.
(i)Construct a playfair matrix with the key moonmission and
encrypt the
message greet.
(ii)Construct a playfair matrix with the key occurrence.
Generate the
cipher text for the plaintext Tall trees.
(iii)Construct a Playfair matrix with the key engineering. And
encrypt the
message test this process.
Department Of Computer Engineering
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(9) Encrypt the message Good morning using the Hill Cipher with
the key
(10)Differentiate block ciphers and stream ciphers.
(11)Explain the terms diffusion and confusion.
(12)Define Steganography and explain various techniques for
steganography.
(13) Explain block cipher modes of operation?
(14) What is the purpose of S-boxes in DES? Explain the
avalanche effect.
(15) Explain the fiestel structure of Blowfish.
(16) Describe the three operations used by International Data
Encryption
Algorithm.
(17)Briefly explain the model of Asymmetric Cryptosystem.
(18) Write Diffie Hellman key exchange algorithm. Explain
man-in-the middle
attack on this Diffie Hellman key exchange.
(19) (i) Write two properties of prime numbers.
(ii) Explain Eulers totient function.
(20)Calculate
(i)ciphertext in case of RSA if p=3,q=11,e=3,M=5.
(ii)In a public key system using RSA, the ciphertext intercepted
is C=10
which is sent to the user whose public key is e=5, n=35. What is
the
Plaintext M?
(21)Which cryptnalytic attack can occur on RSA algorithm?
