Deck 5: Cryptography

Question 1

Which of the following is a current standard for PKI that specifies a strict hierarchical system for CAs issuing certificates?

A) PKCS #2
B) X.509
C) DES
D) SHA-1

Answer 1

B

Question 2

Which type of function is used in cryptography?

A) Not AND
B) permutation
C) NOR
D) X-box

Answer 2

B

Question 3

A hash value is a variable-length string of symbols and numbers representing the original input's contents.

Answer 3

False

Question 4

Which of the following best describes a one-way function?

A) a bit string that prevents generation of the same ciphertext
B) random bits used as input for key derivation functions
C) generates secret keys from a secret value
D) easy to compute but difficult and time consuming to reverse

Question 5

What is the most likely weak link when using asymmetric encryption for verifying message integrity and nonrepudiation?

A) the use of the sender's private key
B) the hashing algorithm used to generate a message digest
C) the source of the public keys
D) the integrity of the private keys

Question 6

Which of the following is true about cryptographic primitives?

A) each performs several tasks
B) a single primitive makes up an entire cryptographic protocol
C) primitives are usually not the source of security failures
D) a primitive that provides confidentiality usually also provides authentication

Question 7

In a passive attack,cryptanalysts eavesdrop on transmissions but don't interact with parties exchanging information.

Question 8

Which of the following is true about Message Authentication Code.

A) it uses asymmetric encryption
B) the key is sent to the receiver securely
C) is uses PKI and certificates
D) it uses a private and public key

Question 9

Which of the following best describes a CRL?

A) a published listing of invalid certificates
B) serve as a front end to users for revoking certificates
C) a file that contains information about the user and public key
D) keeps track of issued credentials and manages revocation of certificates

Question 10

Which of the following is true about PRNGs?

A) they are not completely random
B) their state is measured in bytes
C) the shorter the state, the longer the period
D) they can never produce the same value

Question 11

Which of the following is true about encryption algorithms?

A) their strength is tied to their key length
B) not vulnerable to brute force attacks
C) block ciphers encrypt one bit at a time
D) asymmetric algorithms use a single key

Question 12

Which of the following is the first step in the digital signature process where Mike sends a message to Sophie?

A) a message digest of Mike's message is calculated using a hashing algorithm
B) Sophie compares the message digest she calculated to Mikes's message
C) Sophie encrypts Mike's message with Mike's public key
D) the message digest is encrypted by Mike's private key

Question 13

Encrypted files can be transmitted in both electronic form and as written messages.

Question 14

Because IPsec Security Associations are bidirectional,only one need be established between two parties.

Question 15

Which of the following is commonly used for verifying message integrity?

A) registration authority
B) CRL
C) pseudorandom number generator
D) hashing function

Question 16

Which of the following is true about asymmetric cryptography?

A) the private key can be used to encrypt and decrypt a message
B) a shared key is used to encrypt all messages and the private key decrypts them
C) a single key is used and is transferred using a key management system
D) the public key is used to encrypt a message sent to the private key owner

Question 17

The standardization of cryptographic protocols discourages attackers from trying to break them.

Question 18

Which of the following is NOT a critical goal of information security?

A) confidentiality
B) scalability
C) authentication
D) nonrepudiation

Question 19

Which of the following makes a single pass on data and generates a 128-bit hash value displayed as a 32-character hexadecimal number and is used in VPNs?

A) RSA
B) Message Digest 5
C) RC4
D) Twofish

Question 20

Which of the following is described as a 64-bit block cipher composed of a 16-round Feistel network and key-dependent S-box functions?

A) Twofish
B) RC4
C) Blowfish
D) Rijndael

Question 21

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
unreadable text,programs that do not execute,and graphics you cannot view

Question 22

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
A set of standard procedures that the Internet Engineering Task Force (IETF)developed for enabling secure communication on the Internet

Question 23

At which layer of the OSI model does IPsec work?

A) Two
B) Three
C) Four
D) Six

Question 24

Which of the following was developed as a way of enabling Web servers and browsers to exchange encrypted information and uses a hashed message authentication code to increase security?

A) SSH
B) SSL
C) TLS
D) IPsec

Question 25

Which component of IPsec enables computers to exchange keys to make an SA?

A) IKE
B) ISAKMP
C) Oakley
D) IPsec driver

Question 26

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
readable text,programs that execute,and graphics you can view

Question 27

______________ cryptanalysis is applicable to block ciphers that use a substitution-permutation network including Rijndael,Twofish,and IDEA.

Question 28

A ______________ value is a fixed-size string representing the original input's contents.

Question 29

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
a type of encryption algorithm that encrypts one bit at a time

Question 30

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
a type of encryption algorithm that encrypts groups of cleartext characters

Question 31

Which of the following is a type of cryptanalysis that applies primarily to block ciphers but can also be used against stream ciphers and hashing functions and works by examining how differences in input affect the output?

A) integral
B) differential
C) related key
D) XSL

Question 32

What is a downside to using Triple DES?

A) uses only a 56-bit key
B) goes through three rounds of encryption
C) using three keys decreases security
D) requires more processing time

Question 33

A ________________ occurs when computing the MD5 algorithm with two different initialization vectors produces the same hash value.

Question 34

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
the current U.S.government standard for cryptographic protocols

Question 35

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
an older protocol composed of a 16-round Feistel network with XOR functions,permutation functions,64 S-box functions,and fixed key schedules

Question 36

______________________ is achieved when neither party can plausibly deny its participation in message exchanges.

Question 37

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
the study of breaking encryption methods

Question 38

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
a way to prevent keys from being discovered and used to decipher encrypted messages

Question 39

MATCHING
a.AES
b.block cipher
c.ciphertext
d.cryptanalysis
e.DES
f.XOR function
g.IPsec
h.key management
i.plaintext
j.stream cipher
a cryptographic primitive based on binary bit logic and used as a linear mixing function,combining values for use in further computations

Question 40

Digital ____________________ security vulnerabilities are mostly associated with the IT infrastructure required to support interoperability.

Question 41

What is a hash value and how does it verify message integrity?

Question 42

How does the key size affect the strength of an encryption algorithm?

Question 43

What is a digital signature and for what purpose is one used?

Question 44

What does a key derivation do?

Question 45

Describe the exclusive OR function.

Question 46

What is a MAC tag and how does it work?

Question 47

What three conditions must be true to make a hashing algorithm secure?

Question 48

Compare and contrast block cipher with stream cipher.

Question 49

How does an asymmetric algorithm differ from a symmetric algorithm?

Question 50

What is a Feistel network and what is its purpose?