1.
In cryptography, what is cipher?
a)
algorithm for performing encryption and decryption
b)
encrypted message
c)
both algorithm for performing encryption and decryption and encrypted message
d) decrypted message
Ans: a
2.
In asymmetric key cryptography, the private key is kept by __________
a)
sender
b)
receiver
c)
sender and receiver
d) all the connected
devices to the network
Ans: b
3.
Which one of the following algorithm is not used in asymmetric-key
cryptography?
a)
RSA algorithm
b)
DIFFIE-HELLMAN algorithm
c)
ELECTRONIC CODE BOOK algorithm
d) DSA algorithm
Ans: c
4.
In cryptography, the order of the letters in a message is rearranged by
__________
a)
transpositional ciphers
b)
substitution ciphers
c)
both transpositional ciphers and substitution ciphers
d) quadratic ciphers
Ans: a
5.
What is data encryption standard (DES)?
a)
block cipher
b)
stream cipher
c)
bit cipher
d) byte cipher
Ans: a
6.
Cryptanalysis is used __________
a)
to find some insecurity in a cryptographic scheme
b)
to increase the speed
c)
to encrypt the data
d) to make new ciphers
Ans: a
7.
Which one of the following is a cryptographic protocol used to secure HTTP
connection?
a)
stream control transmission protocol (SCTP)
b)
transport layer security (TLS)
c)
explicit congestion notification (ECN)
d) resource reservation
protocol
Ans: b
8.
In which of the following encryption key is used to encrypt and decrypt the
data?
a)
Public key
b)
Private key
c)
Symmetric key
d) Asymmetric key
Ans: c
9.
ElGamal encryption system is __________
a)
symmetric key encryption algorithm
b)
asymmetric key encryption algorithm
c)
not an encryption algorithm
d) block cipher method
Ans: b
10.
Cryptographic hash function takes an arbitrary block of data and returns
_________
a)
fixed size bit string
b)
variable size bit string
c)
both fixed size bit string and variable size bit string
d) variable sized byte
string
Ans: a
11.
Which of the following statements are true? (i) Stream Ciphers are fasters than
Block Ciphers (ii) Block Ciphers can reuse keys (iii) Block ciphers use lesser
code than stream ciphers
a)
1st and 2nd
b)
1st only
c)
2nd and 3rd
d) All are true
Ans: a
12.
Confusion hides the relationship between the ciphertext and the plaintext.
a)
True
b) False
Ans: b
13. Which of the following slows the cryptographic algorithm – (1) Increase in Number of rounds (2) Decrease in Block size (3) Decrease in Key Size (4) Increase in Sub key Generation
a)
1 and 3
b)
2 and 3
c)
3 and 4
d) 2 and 4
Ans: b
14.
In public key cryptosystem _____ keys are used for encryption and decryption.
a)
Same
b)
Different
c)
Encryption Keys
d) None of the mentioned
Ans: b
15.
In public key cryptosystem which is kept as public?
a)
Encryption keys
b)
Decryption keys
c)
Encryption & Decryption keys
d) None of the mentioned
Ans: a
16.
Private key algorithm is used for _____ encryption and public key algorithm is
used for _____ encryption.
a)
Messages, session key
b)
Session key, messages
c)
Can be used for both
d) None of the mentioned
Ans: a
17.
Which are called the block ciphers?
a)
IDEA
b)
CAST
c)
Triple-DES
d) All of the mentioned
Ans: d
18.
Which algorithm can be used to sign a message?
a)
Public key algorithm
b)
Private key algorithm
c)
Public & Private key algorithm
d) None of the mentioned
Ans: a
19.
In a database where the encryption is applied the data is cannot be handled by
the unauthorised user without
a)
Encryption key
b)
Decryption key
c)
Primary key
d) Authorised key
Ans: b
20.
Which of the following is not a property of good encryption technique?
a)
Relatively simple for authorized users to encrypt and decrypt data
b)
Decryption key is extremely difficult for an intruder to determine
c)
Encryption depends on a parameter of the algorithm called the encryption key
d) None of the mentioned
Ans: d
