Quiz 3

Question 1

3DES is \_\_\_\_\_\_\_\_.
strong enough for communication in corporations
very slow
expensive in terms of processing cost
All of the above

Answer 1

All of the above

Question 2

A DES key is 40 bits long. (True False)

Answer 2

False

Question 3

An attack where an adversary intercepts an encrypted message and transmits it again later is called a \_\_\_\_\_\_\_\_.
replay attack
reex attack
resend attack
reection attack

Answer 3

replay attack

Question 4

DES uses block encryption.

True False

Answer 4

True

Question 5

HMACs provide the cryptographic protection of \_\_\_\_\_\_\_\_.
message integrity
message authentication
Both A and B
Neither A nor B

Answer 5

Both A and B

Question 6

Hashing is \_\_\_\_\_\_\_\_.
repeatable
reversible
Both A and B
Neither A nor B

Answer 6

repeatable

Question 7

Julia encrypts a message to David using public key encryption for condentiality. After encrypting the message, can Julia
decrypt it?
(True / False)

Answer 7

False

Question 8

In public key encryption, “signing” is the act of ________.
adding the password to the challenge message and hashing the two
hashing the plain text message
encrypting the message digest with its own private key
encrypting the message digest with its own public key

Answer 8

encrypting the message digest with its own private key

Question 9

In public key encryption for authentication, the verifier decrypts the ciphertext with the verifier’s public key.
(True False)

Answer 9

False

Question 10

If a key is 43 bits long, how much longer will it take to crack it by exhaustive search if it is extended to 50 bits?
14 times as long
7 times as long
256 times as long
128 times as long

Answer 10

128 times as long

Question 11

The best way to thwart exhaustive searches by cryptanalysts is \_\_\_\_\_\_\_\_.
to make the key very long
to use codes
randomize the key thoroughly
All of the above

Answer 11

to make the key very long

Question 12

Symmetric session key exchange can be done with public key encryption.
(True / False)

Answer 12

True

Question 13

When two parties communicate with each other using symmetric key encryption, how many keys are used in total to
encrypt and decrypt?
8
1
4
2

Answer 13

1

Question 14

When a hashing algorithm is applied, the hash will ALWAYS have a fixed length (True / False)

Answer 14

True

Question 15

When Carol sends a message to Bob, Bob will use \_\_\_\_\_\_\_\_ to decrypt the message.
Carol's public key
Bob's private key
Carol's private key
the private key

Answer 15

Bob’s private key

Question 16

What is the hash size of SHA-256?
112 bits
128 bits
160 bits
256 bits

Answer 16

256 bits

Question 17

Using new and proprietary encryption ciphers is a good idea because cryptanalysts will not know them.
(True / False)

Answer 17

False

Question 18

To ensure that a digital certicate is valid, the receiver of the certicate must check \_\_\_\_\_\_\_\_.
whether the certicate has been revoked
the digital signature
the valid period
All of the above.

Answer 18

All of the above.

Question 19

The most popular public key cipher is RSA (True / False)

Answer 19

True

Question 20

\_\_\_\_\_\_\_\_ occurs when companies believe they have good security because they are using proprietary ciphers that
hackers do not know.
Reasonable protection
Security through obscurity
Weakest link ignorance

Answer 20

Security through obscurity

Question 21

\_\_\_\_\_\_\_\_ is the use of mathematical operations to protect messages travelling between parties or stored on a computer.
Confidentiality
Cryptography
Encryption
Authentication

Answer 21

Cryptography

Question 22

Which of the following measures do HMACs use?
Public key encryption
Symmetric key encryption
Hashing
All of the above

Answer 22

Hashing

Question 23

Which of the following is one of the effective key lengths in 3DES?
110 bits
40 bits
Both A and B
Neither A nor B

Answer 23

Neither A nor B

Question 24

Programmers frequently create entry points into a program for debugging purposes and/or insertion of new program
codes at a later date. What are these entry points called?
Backdoors
Logic Bombs
Trojan Horses
Worms

Answer 24

Backdoors

Question 25

Which of the following infects both boot-sectors and le-infectors?
Worm
Link Virus 
Macro
Multi-partite

Answer 25

Multi-partite

Question 26

A polymorphic virus uses which of the following?
Heuristic engine 
Search engine 
Mutation engine 
Inference engine

Answer 26

Mutation engine

Question 27

What is the name of the malicious act of a computer program looking normal but containing harmful code?
Trapdoor 
Trojan Horse 
Worm
Logic Bomb

Answer 27

Trojan Horse

Question 28

.........................................works by creating an artificial TCP segment that has the SYN flag set
land DoS
TearDrop
Smurf
Sning

Answer 28

land DoS

Question 29

TearDrop is a fragmentation attack on the ........................ protocol stack. 
TCP/IP
UDP
ICMP
TOC/TOU

Answer 29

TCP/IP

Question 30

Which of the following script is example of SQL injection attack?
var Shipcity; ShipCity = Request.form (“ShipCity”);

var Shipcity; ShipCity = Request.form (“ShipCity”); var SQL = “select * from OrdersTable where ShipCity = ‘” + ShipCity + “’”;

var Shipcity; var SQL = “select * from OrdersTable where ShipCity = ‘” + ShipCity + “’”;

All of options

Answer 30

var Shipcity; ShipCity = Request.form (“ShipCity”); var SQL = “select * from OrdersTable where ShipCity = ‘” + ShipCity + “’”;

Question 31

Which term best describes the act of actively searching for a computer's ports through the use of
specialized software
port searching 
port vulnerabilities 
sning 
port scanning

Answer 31

port scanning

Question 32

What typically happens when a buffer is overflowed?
The memory space that comes after the buffer holds the extra data as well as keeping the data that it contained
before
Whatever is in the memory space that comes after the buer is overwritten
The memory chip in the computer gets too big and explodes
Electrons fall out of the memory chip and start a re

Answer 32

Whatever is in the memory space that comes after the buffer is overwritten

Question 33

which option is wrong?
The smurf attack is a distributed reflective denial-of-service (DRDoS) attack
DNS amplification causes flooding.
Ping of death attack uses ICMP packet.
DNS poisoning is not a DoS attack.

Answer 33

DNS poisoning is not a DoS attack.

Question 34

which method is not a reconnaissance attack?
IP probe 
Dumpster diving 
Port scan 
Buffer overflow

Answer 34

Buffer overflow

Question 35

In a replay attack, the attacker cannot read the contents of the replayed message.

Answer 35

True