WorksheetsCryptography & Network Security
Total questions: 15
Worksheet time: 8mins
1. is the science and art of transforming messages to make them secure and immune to attacks
Cryptography
Cryptoanalysis
either (a) or (b)
neither (a) nor (b)
The is the original message before transformation
ciphertext
plaintext
secret-text
none of the above
3. The is the message after transformation
ciphertext
plaintext
secret-text
none of the above
4.A(n) algorithm transforms plaintext to ciphertext
encryption
decryption
either (a) or (b)
neither (a) nor (b)
A combination of an encryption algorithm and a decryption algorithm is called a _______________
cipher
secret
key
none of the above
In an asymmetric-key cipher, the sender uses the_ key
private
public
either (a) or (b)
neither (a) nor (b)
ciphers can be categorized into two broad categories: mono alphabetic and Poly alphabetic
Substitution
Transposition
either (a) or (b)
neither (a) nor (b)
DES uses a key generator to generate sixteen ____round keys
32-bit
48-bit
54-bit
42-bit
In brute force attack, on average half of all possible keys must be tried to achieve success.
True
False
What is 11 mod 7 and -11 mod 7?
a) 4 and 5
b) 4 and 4
c) 5 and 3
d) 4 and -4
In symmetric-key cryptography, the key locks and unlocks the box is (a)
What is Data Encryption Standard? (DES)
(a)
Cryptography, a word with Greek origins, means
Corrupting data
Secret Writing
Open writing
Closed writing
[(a mod n) + (b mod n)] mod n = (a+b) mod n
True
False
If the sender and receiver use different keys, the system is referred to as conventional cipher system.
True
False
