Network Security - MCQS

Question
Consider these statements and state which are true.
i)   Encoding and encryption change the data format.
ii)  Encoding is a reversible process, while encryption is not.
iii) Both Encoding and Encryption are reversible processes.
iv)  Any third party will be able to reverse an encoded data,but not an encrypted data.

Select one:
i), iii) and iv)
ii) and iv)
i) and iv)
i), ii) and iv)

The correct answer is: i), iii) and iv)

Question
Which of the following attacks is not an attack on Integrity?

Select one:
Modification
Replay
Denial Of Service
Masquerading

The correct answer is:: Denial Of Service

Question
I sent a data set {A,B,C,D} to a recipient which got received as {B,A,D,C}.

Select one:
Data security is compromised
Data integrity is lost
Confidentiality is lost
Data availability is compromised

The correct answer is:: Data integrity is lost

Question
A website login mechanim employs both password and verifying a PIN number sent via SMS to registered mobile.

This scenario provides ______
Select one:
High convenience but low security
High convenience and good security
Low convenience and low security
Low convenience but good security

The correct answer is:: Low convenience but good security

Question
A fake email posing as a legitimate email from bank is 

Select one:
Attack on Availability
Masquerading attack
Denial of Service (DOS) attack
Attack on Confidentiality

The correct answer is:: Masquerading attack

Question
Which of these mechanims provide data integrity ?
i) DES Encryption
ii) Asymmetric encryption
iii) SHA Hashing
iv) Hashed-MAC

Select one:
i and iv
i and iii
ii and iii
iii and iv

The correct answer is:: iii and iv

Question
Email attachments typically employ

Select one:
Base64 encoding
Base16 encoding
UTF-8 encoding
URL encoding

The correct answer is:: Base64 encoding

Question
The combination of key exchange, hash and encryption algorithms is termed as _______ in SSL/TLS.     

Select one:
TLS Handshake
Protocol suite
Cipher suite
TLS Records

The correct answer is:: Cipher suite

Question
The protocol ‘POP’ stands for-

Select one:
Personal Office Protocol
Post Office Protocol
Privacy Overall Protocol
Privacy Over Protocol

The correct answer is:: Post Office Protocol

Question
Which is the most secure way to remote login?

Select one:
SSH with public keys
Telnet with password
SSH with password
Telnet with public keys

The correct answer is:: SSH with public keys


Question
The Application layer protocol required for Electronic Mail is:

Select one:
SMTP
HTTP
FTP
SIP

The correct answer is: SMTP

Question
Which of these statements regarding HTTP is true.

Select one:
HTTPS adds security to HTTP POST and PUT messages as this is where password exchange is done.
HTTPS uses the same HTTP message format but  adds a handshake+encryption mechanism.
HTTPS introduces new messages HANDSHAKE and ALERT for bringing in security in HTTP.
HTTPS does not add security to HTTP GET and HEAD messages

The correct answer is: HTTPS uses the same HTTP message format but  adds a handshake + encryption mechanism.

Question
Which of these statements is true?

Select one:
a. IMAP provides security, but is optional in email
b. SMTP has a mechanism to enable TLS mode to enforce security.
c. Email mandates use of IMAP so that security is enforced
d. If TLS mode in SMTP is set forwarding will fail

The correct answer is:  SMTP has a mechanism to enable TLS mode to enforce security.

Question
For SSL which is the advised cryptographic algorithm?

Select one:
twofish 128
aes 192
aes 128
blowfish

The correct answer is:: aes 128

Question
In SSL handshake, Server Hello message typically contains

Select one:
List of ciphers for the session and extensions list
Selected cipher for the session and random bytes
Selected cipher for the session and public key of server
Random bytes and public key of server

The correct answer is: Selected cipher for the session and random bytes

Question
Pretty Good Privacy (PGP) is employed in

Select one:
FTP and WWW Security
Email and FTP Security
Email security
Email and WWW Security

The correct answer is:: Email security

Question
What is the common term present in HTTP request and status line?

Select one:
HTTP version number
URL
Method
None of the mentioned

The correct answer is:: HTTP version number

Question
A session symmetric key between two keys is used:

Select one:
Only once
Two times
Multiple times
Dependent on other conditions

The correct answer is:: Only once

Question
Which one of the following is a cryptographic protocol used to secure HTTP connection?

Select one:
Stream Control Transmission Protocol (SCTP)
Pretty Good Privacy (PGP)
Secure Mime(SMIME)
Transport Layer Security (TLS)

The correct answer is:: Transport Layer Security (TLS)

Question
The services provided by application layer are:

Select one:
Network virtual terminal
File transfer, access, and management
Mail service
All of the mentioned

The correct answer is:: All of the mentioned

Question
A group having 30 members uses Symmetric Key Encryption for message transmission.   How many secret keys are needed if all the members need to send secret messages to each other?

Select one:
30
60
435
900

The correct answer is: 435

Question
DES is no longer a recommended cipher because...

Select one:
A. it produces reflexive keys in pairs which are weak
B. it requires more computing power
C. it can be brute forced as it is 56-bit
D. major flaws were found in the rounds of DES

The correct answer is: it can be brute forced as it is 56-bit

Question
I - me@gmail.com - tried to email a .jar file to Dinesh. dinesh@company.com . But it got blocked by gmail while attaching.Then I tried sending a .txt file to Dinesh which went through fine. What do you infer? .jar files cannot be sent as

Select one:
A. it is blocked by gmail as .jar files are bigger in size
B. Email uses SMTP which is a Text protocol
C. it is blocked by company.com
D. it is blocked by gmail as it could contain viruses.

The correct answer is: it is blocked by gmail as it could contain viruses.

Question
What is the protocol used between Message User Agent (MUA) and Message Transfer Agent (MTA) in email system.

Select one:
A. HTTP
B. SMTP
C. IMAP
D. POP3

The correct answer is: SMTP


Question
IPSec defines these two protocols:

Select one:
A. PGP; ESP
B. AH; ESP
C. AH; SSL
D. PGP: SSL

The correct answer is: AH; ESP

Question
HTTPS implicitly uses Server certificates. These Server certificates contain ______

Select one:
A. Server's public key, algorithm used and digital signature
B. Server's public key and private key
C. Server's private key, algorithm used and digital signature
D. Server's public key and digital signature

The correct answer is: Server's public key, algorithm used and digital signature

Question
Asymmetric encryption has

Select one:
A. one key for encryption and another key for decryption
B. two keys - one key for public encryption and another for private encryption
C. one public key for doing encryption and decryption and another private key only for decryption
D. only one public key which is shared

The correct answer is: one key for encryption and another key for decryption

Question
Instead of storing plaintext passwords, AES encrypted passwords are stored in database.

In such a system, Which of these statements is true ?

Select one:
a. if database admin knows the key, there is no security
b. Password Authentication becomes slow
c. Changing passwords will not be possible
d. even if database admin knows the key, original passwords cannot get revealed.


The correct answer is: if database admin knows the key, there is no security

Question
IP Header contains

Select one:
A. Source and destination IP addresses and priority numbers
B. Source and destination IP addresses and IP version number
C. Source and destination IP addresses and Port numbers
D. Source and destination IP addresses and sequence numbers

The correct answer is: Source and destination IP addresses and IP version number



Question
Pick the most relevant option. I sent a data set {J,K,L,M,N} to a recipient which got received as {J,K,N}.

Select one:
A. Data integrity is lost
B. Data availability is compromised
C. Both Confidentiality and integrity are compromised
D. Data Confidentiality is compromised

The correct answer is: Data integrity is lost

Question
A data center is secured with 3 outer gates - Og1, Og2, Og3    locked by separate keys - Kog1, Kog2, Kog3 - given to    three personnel - P1, P2, P3.
These 3 outer gates lead to 2 inner gates - Ig1, Ig2 - which provide main corridor access. The matching keys - Kig1, Kig2 are given to P2 and P4. The order of acessibility from most access to least access for the personnel is ____________

Select one:
A. P2, P1, P3, P4
B. P1, P2, P3, P4
C. P4, P3, P2, P1
D. P2, P4, P1, P3

The correct answer is: P2, P1, P3, P4

Question
Pick the closest in meaning to non-repudiation. Manu sends data to Naren. Paari is sniffing the data transfer.

Select one:
A. Naren can verify that data was indeed sent by Manu.
B. Paari is unable to get the original data.
C. Manu can verify if data reached Naren without any change.
D. Naren can verify if the data got changed by Paari

The correct answer is: Naren can verify that data was indeed sent by Manu.

Question
The modes  of IP-Sec are

Select one:
A. Padding mode and Non-padding mode.
B. Secure and Unsecure Mode
C. Tunnel Mode and Transport Mode
D. SPD and SAD mode

The correct answer is: Tunnel Mode and Transport Mode

Question
Of these, Which is the most secure way to remote login?

Select one:
A. SSH with public keys
B. Telnet with password
C. Telnet with public keys
D. SSH with password

The correct answer is: SSH with public keys

Question
Megha's uses a 4-digit bank ATM PIN. Guna peeped in,as Megha keyed-in and found the last two digits of her PIN. Knowing that Megha does not use 0 in her PIN, what is the maximum attempts for Guna to get her PIN correct ?

Select one:
A. 18
B. 81
C. 19
D. 90

The correct answer is: 81

Question
When using HTTPS, a sniffer in a local LAN will be able to

Select one:
A. sniff only the websites/domain but not the URLs
B. sniff only the websties/domain but not the IP addresses
C. sniff only the URLs in the data exchange but not the posted/downloaded data contents.
D. sniff only the HTTP headers in the requests and response

The correct answer is: sniff only the websites/domain but not the URLs

Question

Pick the statement which is true. A network application

Select one:

A. can use both TCP and UDP at the same time, but only maximum of 256 ports. Incorrect

B. cannot use both TCP and UDP at the same time.

C. can use both TCP and UDP at the same time

D. can use both TCP and UDP at the same time, but only maximum of 1024 ports.

The correct answer is: can use both TCP and UDP at the same time

Question
Find the modular inverse of a number in mod arithmetic using

Select one:
a. Extended Euclidean Algorithm
b. Diffie Hellmann Algorithm
c. El-Gamal Algorithm
d. Euclids Algorithm

The correct answer is: Extended Euclidean Algorithm

Question
Which is the generator for modulo base 11 ?

Select one:
A. 2
B. 5
C. 3
D. 1

The correct answer is: 2

Question
399915 ^ 505021 mod 9 = ?

Select one:
a. 1
b. 0
c. 3
d. 6

The correct answer is: 0

Question
210031 ^ X mod 19 = 1

Here the matching values for X are
Select one:
a. 6, 9, 18
b. 18, 9, 36
c. 8, 18, 27
d. 6, 12, 18

The correct answer is: 18, 9, 36

Question
Euler’s Totient Function Φ (10) is:

Select one:
2
5
4
8

The correct answer is: 4

Question
Which of the following algorithms do not make use of primitive roots in its computations?
Select one:
RC4
Diffie Hellman Key Exchange
Elgamal Cryptographic System
None of the above

The correct answer is: RC4

Question
BBS generator is used for generating:

Select one:
Symmetric keys
Asymmetric keys
Random Numbers
All of above

The correct answer is: Random Numbers

Question 4
-22 mod 11 equals

Select one:
0
5
2
3

The correct answer is: 0

Question 5
Which of the following is not a criteria for design in DES cipher?

Select one:
Varying the block size
Varying the number of rounds of the cipher
Varying the key size for each round of the cipher
Varying the algorithm for generation of the subkey

The correct answer is: Varying the key size for each round of the cipher

Question
Consider Hashed Message Authentication Code (HMAC) scheme.
Pick which statement is true.

Select one:
A. HMAC output depends on the size of the input message
B. HMAC output size is not fixed
C. HMAC output size is same as the input key size
D. HMAC output size depends on the hashing tool chosen

The correct answer is: HMAC output size depends on the hashing tool chosen

Question
Public key encryption/decryption is not preferred because

Select one:
it is slow
it is hardware/software intensive
it has a high computational load
all of the mentioned

The correct answer is: all of the mentioned

Question
A real number that cannot be represented as a ratio of two integers is known as:

Select one:
Whole Number
Prime Number
Irrational Number
Recurring decimal

The correct answer is: Irrational Number

Question
Which one of the following is not a legitimate entropy source for TRNG algorithm?

Select one:
Disk rotation in RPM
Clock speed
Key strokes
Screen size

The correct answer is: Screen size

Question
The first 8 bits for BBS bit generator when seed = 101355 and n=192649 is

Select one:
10101010
11100010
11001011
11001110

The correct answer is: 11001110

Question
Statistical relationship between the rule to encrypt and the ciphertext produce should be as complex as possible.  This principal is known as:

Select one:
Diffusion
Confusion
Complex encryption
None of the above

The correct answer is: Confusion

Question
What is the GCD (1701, 3768)?

Select one:
4
1
3
7

The correct answer is: 3

Question
Pick the valid MIME header, when sending an image in email.

Select one:
A. Content-type: image/gif
Content-Disposition: attachment; filename="star.gif"
B. Content-type: image/gif/jpeg/jpg; name="star.gif"
Content-Disposition: attachment; filename="star.gif"
C. Content-type: image/gif; name="star.gif"
Content-Disposition: base64; filename="star.gif"
D. Content-type: image/gif; name="star.gif"
Content-Disposition: image; filename="star.gif"

The correct answer is: Content-type: image/gif
Content-Disposition: attachment; filename="star.gif"

Question
Let m be a message consisting of 64 blocks which Anubhav transmits to Bani using block mode of encryption.  Due to a network error, the 12th block gets corrupted, but all other cipher text blocks are transmitted ly.  Once Bani decrypts the cipher text, how many plaintext blocks will be affected,
assuming CFB and ECB modes of operations?

Select one:
53 for CFB, 1 for ECB
1 for CFB, 53 for ECB
52 for CFB, 1 for ECB
52 for both CFB & ECB

The correct answer is: 53 for CFB, 1 for ECB

Question
Disadvnatge of Vernam Cipher over RC4 is:

Select one:
Can’t decrypt large size message
Key needs to be same as plain text size
Complex Encryption approach
All of the above

The correct answer is: Key needs to be same as plain text size

Question
An Asymmetric –key (public-key) cipher uses:

Select one:
1 Key
2 Key
3 Key
4 Key

The correct answer is: 2 Key

Question
3 and 19 are congruent in:

Select one:
Z10
Z7
Z8
Z11

The correct answer is: Z8

Question
What is multiplicative invers of 20 with arithmetic modulo 73

Select one:
11
17
37
21

The correct answer is: 11


Question
In a good cipher system, if you changed every bit in the plaintext, approximately. What percentage of the cipher text should change?

Select one:
1%
50%
100%
None of A, B or C is 

The correct answer is: 50%

Question
What are Challenges in Block Ciphering?

Select one:
Selection of block ciphering algorithm to encrypt and decrypt.
Easy to crack
Difficult to understand
All of the above

The correct answer is: Selection of block ciphering algorithm to encrypt and decrypt.

Question
Given 2^X mod 59 = 1. What is the value of X?

Select one:
58
116
Both A & B
None of the above

The correct answer is: Both A & B

Question
Pick which statement is true.

Select one:
a. Secure Hash cannot be reversed, but a secure cipher can be.
b. Both Secure Hash and secure cipher cannot be reversed, but only in the case of hash the output size is fixed.
c. Both Secure Hash and secure cipher can be reversed, but only in the case of hash the output size is fixed.
d. Secure Hash can be reversed, but a secure cipher cannot

The correct answer is: Secure Hash cannot be reversed, but a secure cipher can be


Question
What is the maximum value that a 56 bit DES key can have?

Select one:
7.2 x 1016
6.3x1012
4.5x1011
8.2x1018

The correct answer is: 7.2 x 1016

Question
Choose the prime number from the given list

Select one:
A. 1206117
B. 12411
C. 930931
D. 39229

The correct answer is: 39229

Question
Which are these sets are co-primes ?
Set i - 22,101
Set ii - 23,345
Set iii - 350,91
Set iv - 31,48

Select one:
a. i and iv
b. only iv
c. i, ii, and iii
d. iv and iii

The correct answer is: a [Set i and Set iv are co-prime]

Question
Which of the following methods relies on prime number factoring for its strength?

Select one:
A. DES
B. RSA
C. El-Gamal
D. Elliptic Curve

The correct answer is: RSA

Question
Pick which statement is true.
Triple DES...

Select one:
A. 128 bit keys on 64-bit blocks, DES once
B. 192-bit blocks of plain text, DES thrice
C. 128-bit blocks of plain text, 112 bit keys, DES thrice
D. 64-bit blocks of plain text, 56 bit keys, DES thrice

The correct answer is: 64-bit blocks of plain text, 56 bit keys, DES thrice

Question
Which of these DNS records are used for SPAM filtering?

Select one:
A. A and MX
B. A, MX and SPF
C. PTR and SPF
D. MX and SPF

The correct answer is: PTR and SPF

Question
I gave two hashes to my friend :
H1 = MD5(my password)
H2 = MD5(reverse of my password)
The next day he was able to tell my password. What do I infer from this exercise?

Select one:
a. My password was too weak and guessable
b. MD5 is weak and can be cracked
c. Revealing the reverse hash of the password is enough to figure out the password
d. My password did not contain special characters

The correct answer is: My password was too weak and guessable

Question
Pick which statement is true.
Elliptic curve -Digital Signature generation...

Select one:
A. is encryption of the plaintext by sender using the elliptic curve private key of the receiver.
B. encrypts the plaintext and produces a signature such that the plaintext is confidential.
C. is encryption of the plaintext by sender using the elliptic curve public key of the receiver
D. provides data integrity for plaintext

The correct answer: provides data integrity for plaintext

Question
Consider (a ^ n) mod p = 1, and pick which of the following is true.

Select one:
A. If p is not prime and a and p are co-prime, then n=p-1
B. If n = p-1, it implies that p is prime.
C. If and only if p is prime, n = p-1
D. If p is prime,  then n=p-1

The correct answer is: If p is not prime and a and p are co-prime, then n=p-1

Question
Why is it not possible to host multiple web domains under
the same IP address in https?

Select one:
a. https mandates IP address tied to SSL certificates
b. It is very much possible if https uses SNI option
c. IP addresses are verified in https
d. It is very much possible by using load balancer

The correct answer is: It is very much possible by using load balancer