SETHU INSTITUTE OF TECHNOLOGY
(An Autonomous Institution)
Pulloor - 626 115, Kariapatti (TK), Virudhunagar District.
PERIODICAL TEST – I
21UCS702 –Cryptography and Cyber Security
Question Bank
Regulation – 21
PART –A
Q.No Questions M CO BL PO
1 7What are the 3 aspects of security? 2 CO1 U -
2 8Write the Euclidean Algorithm. 2 CO1 U -
3 9Define Steganography. 2 CO1 U -
4 1Define Finite Group CO1 U
2 -
0
Decipher the following cipher Text using brute force attack:
5 1
CMTMROOEOORW depth 2 (Hint: Algorithm-Rail fence) 2 CO2 AP PO1
6 1Decipher the following cipher Text using caeser cipher
2 CO2 AP PO1
2technique: plain text-MONARKEY, Key = 3
7 Compare passive and active attack 2 CO1 U -
8 Why is asymmetric cryptography bad for huge data? Specify the reason 2 CO1 U -
9 Write short notes on CryptAnalysis. 2 CO1 U -
10 Difference between Substitution and Transposition techniques. 2 CO1 U -
11 Define cryptography 2 CO1 U -
Decipher the following cipher Text using brute force attack:
12
CMTMROOEOORW depth 2 (Hint: Algorithm-Rail fence) 2 CO2 AP PO1
Convert the Given Text “VALLIAMMAI” into cipher text using
13 2 CO2 AP PO1
Rail fence Technique
14 Compare Block and Stream cipher. 2 CO1 U -
15 Define Model of network security? 2 CO1 U -
16 Explain idea of RC4 stream cipher.. 2 CO1 U -
17 Define Model of network security 2 CO1 U -
Decipher the following cipher Text using brute force attack:
18
“HEIIOWORLD” depth 2 (Hint: Algorithm-Rail fence) 2 CO2 AP PO1
Decipher the following cipher Text using caeser cipher
19 2 CO2 AP PO1
technique: plain text-CRYPTOGRAPHY, Key = 2
20 Why is symmetric cryptography bad for huge data? Specify the reason 2 CO1 U -
PART –B
Encrypt the message “PAY” using hill cipher with the following key
matrix and show the decryption to get the original plaintext.
10 17 17 5 16 CO2 AP PO1
KEY=[21 18 21]
2 2 2
Encrypt the following using play fair cipher using the
11 keyword MONARCHY. Use X for blank 16 CO2 AP PO1
spaces “SWARAJ IS MY BIRTH RIGHT”
Apply the structure of AES encryption process with suitable example.
12 Indicate the comparable element in AES and DES and 16 CO2 AP PO1
Diagrammatically.
Illustrates the overall structure of the simplified DES, which we will
refer to as SDES. The S-DES encryption algorithm takes an 8-bit block
of plaintext (example: 10111101) and a 10-bit key as input and
13 produces an 8-bit block of ciphertext as output. The S-DES decryption 16 CO2 AP PO1
algorithm takes an 8-bit block of ciphertext and the same 10-bit key
used to produce that ciphertext as input and produces the original 8-bit
block of plaintext.
(i)Discuss the various security mechanisms. (8M)
(ii) Summarize OSI security architecture model with neat diagram.
14 16 CO1 U -
(8M)
(i) Discuss the substitution Techniques in detail. (8M)
15 (ii) Discuss the Transposition Techniques in detail.(8M) 16 CO1 U -
Solve gcd(98, 56) using Extended Euclidean algorithm. Write the
16 algorithm also 16 CO2 AP PO1
Design 1113 mod 53 using modular exponentiation
17 16 CO2 AP PO1
Prove the Following
(i). If p is a prime and a is a positive integer relatively prime to p, then
a p-1≡ 1(mod p) (8M)
18 16 CO2 AP PO1
(ii).If p is a prime and a is a positive integer, then a p ≡ a (mod p). (8M)
Find the secret key shared between user A and user B using
DiffieHellman algorithm for the following q=353;α(primitive
19 root)=3,XA=45 and XB=50 16 CO2 AP PO1
Experiment with Taxonomy of potential attacks on RSA
20 16 CO1 U -
With a neat sketch explain the Elliptic curve cryptography with an
21 example. 16 CO1 U -
Encrypt the following using play fair cipher using the
22 keyword “MONDAY”. Use X for blank 16 CO2 AP PO1
spaces “BIRTHDAY MONTH IS JULY”
For each of the following elements of DES, indicate the
comparable element in AES if available. i) XOR of sub key
material with the input to the function (4)
23 ii) f function (4) 16 CO1 U -
iii) Permutation p (4)
iv) Swapping of halves of the block.(4)
Measure the Public key-distribution and Symmetric Key-Distribution
24 16 CO1 U -
Solve gcd(83’19) using Extended Euclidean algorithm. Write the
25 algorithm also 16 CO2 AP PO1
(i)Illustrate the rules to perform encryption using play fair cipher
and encrypt ‘snowshooos’ using ‘monarchy’ I and J count as one
26 letter and x is the filler letter. (8) 16 CO2 AP PO1
(ii) Encrypt the word “Semester Result” with the keyword
“Examination” using playfair cipher.(8)
(i)Given Cipher text “YMJTYMJWXNIJTKXNQJSHJ”, the
27
message is encrypted by Caesar cipher and k=5. Try to decrypt 16 CO2 AP PO1
the message. (8)
(ii) Using Vigenere cipher, encrypt the word “explanation” using the
Key leg.(8)
Illustrates the overall structure of the simplified DES, which we will
refer to as SDES. The S-DES encryption algorithm takes an 8-bit block
of plaintext (example: 10111101) and a 10-bit key as input and
28 produces an 8-bit block of ciphertext as output. The S-DES decryption 16 CO2 AP PO1
algorithm takes an 8-bit block of ciphertext and the same 10-bit key
used to produce that ciphertext as input and produces the original 8-bit
block of plaintext.
Describe DES algorithm with neat diagram and explain the steps.
29 16 CO1 U -
Experiment with Taxonomy of potential attacks on RSA.
30 16 CO1 U -
