Deck 3: Cryptography

Question 1

Any original message is called ________.

A) plaintext
B) ciphertext
C) message digest
D) the hash

Answer 1

plaintext

Question 2

________ is a cryptographic process that changes plaintext into a seemingly random stream of bits.

A) Encryption
B) Brute-force key cracking
C) Cryptography
D) Ciphertext

Answer 2

Encryption

Question 3

What does encryption and decryption require?

A) Plaintext and ciphertext
B) A cipher and a key
C) A message and a key
D) DES and 3DES

Answer 3

A cipher and a key

Question 4

Auguste Kerckhoffs proved that as long as the ________, the two parties will still have confidentiality.

A) both the key and the cipher code are kept secret
B) the key is made available and the cipher is kept secret
C) the key is kept secret
D) the cipher is kept secret

Question 5

________ ciphertext is to turn it back into its original plaintext.

A) Decrypting
B) Coding
C) Encrypting
D) Keying

Question 6

What does Kerckhoffs' Law say is the recipe for secure encryption?

A) Keeping keys secret
B) Keeping ciphers secret
C) Keeping keys available to only two users
D) Keeping ciphers available to only two users

Question 7

Which of the following is simply the act of trying all possible keys until the right key is discovered?

A) Encryption
B) Brute-force key cracking
C) Mutual authentication
D) Keying

Question 8

What happens in substitution ciphers?

A) The order of the two characters is reversed.
B) One character is substituted for the other, and then the order of the two is switched.
C) One character is substituted for another, but the order of characters is not changed.
D) Both characters are kept secret, but the key is revealed.

Question 9

In ________, the letters are moved around within a message, based on their initial positions in the message.

A) brute-force key cracking
B) mutual authentication
C) substitution ciphers
D) transposition ciphers

Question 10

Which of the following is FALSE in regard to symmetric key encryption?

A) Symmetric key encryption is very fast.
B) All but a tiny fraction of encryptions for confidentiality uses symmetric key encryption.
C) Very few personal computers or handheld devices have sufficient processing power to encrypt with symmetric key encryption.
D) Symmetric key encryption places only a small processing burden on computers.

Question 11

Which of the following is describes keys that are prohibitively time-consuming to crack?

A) Strong symmetric keys
B) 40-bit keys
C) 56-bit keys
D) 112-bit 3DESs

Question 12

Information security is a fairly recent issue-primarily in just the last 80-100 years.

Question 13

Encryption for confidentiality was the original purpose of cryptography.

Question 14

All ciphers operate the same.

Question 15

A key is a random strong of 40 to 4,000 bits.

Question 16

Almost all computer information is encoded as a set of bytes and characters.

Question 17

A cryptanalyst is someone who cracks encryption.

Question 18

In transposition ciphers, letters are changed but their position is not.

Question 19

A cipher is a general way to encrypt information, while codes are limited.

Question 20

Doubling the key length increases the number of possible keys by approximately double.

Question 21

The weakest cipher in common use today is ________.

A) DES
B) RC4
C) 3DES
D) AES

Question 22

________ is 56 bits long.

A) The DES key
B) An RSA key
C) A symmetric key
D) A hash

Question 23

Which of the following is FALSE about 3DES?

A) It is very slow.
B) It is expensive in regard to processing cost.
C) 3DES gives strong symmetric key encryption.
D) 3DES has a key length of 56.

Question 24

Which of the following is efficient in regard to processing power and RAM requirements to be used on many different types of devices?

A) 3DES
B) DES
C) Triple DES
D) AES

Question 25

AES offers four different alternative key lengths.

Question 26

Creating a vulnerability-free encryption cipher is extremely difficult.

Question 27

A cryptographic system is ________.

A) a system where letters are moved around within a message, based on their initial positions in the message
B) a packaged set of cryptographic countermeasures for protecting dialogues
C) a specific set of options in SSL/TLS
D) when both parties authenticate themselves

Question 28

Which of the following is NOT one of the three handshaking stages of a cryptographic system standard?

A) Negotiation
B) Authentication
C) Communicating
D) Keying

Question 29

A specific set of options in SSL/TLS is called a(n) ________.

A) DES key
B) cipher suite
C) RSA key
D) symmetric key

Question 30

When are the handshaking stages over in a cryptographic system standard?

A) After the two sides have authenticated each other and keys have been exchanged
B) After an electronic signature is sent and received by each party
C) After the sender encrypts the combined message and electronic signature for confidentiality
D) After the two sides have authenticated each other and messages have been exchanged

Question 31

The third stage of handshaking of a cryptographic system standard is ________.

A) negotiation
B) authentication
C) communicating
D) keying

Question 32

There are three handshaking stages when two parties communicate through a cryptographic system standard.

Question 33

The second stage of a cryptographic system standard is initial authentication.

Question 34

Message-by-message authentication thwarts efforts by impostors to insert messages into a dialogue stream.

Question 35

Message integrity refers to the idea that if an attacker captures and alters a message, the authentication process will reject the message.

Question 36

A cipher suite includes all of the following EXCEPT ________.

A) a specific set of methods and options for initial authentication
B) a key exchange
C) ongoing message confidentiality, authentication, and integrity
D) an encrypted message and an electronic signature

Question 37

The weakest cipher suites in a cryptographic system standard may provide no protection at all.

Question 38

There is wide variation in the strengths of SSL/TLS cipher suites.

Question 39

Once security negotiation is finished, the next handshaking stage in establishing a cryptographic system dialog is ________.

A) communication
B) authentication
C) confidentiality
D) encryption

Question 40

In authentication in a cryptographic system, the party trying to prove its identity is called the ________.

A) key
B) verifier
C) supplicant
D) hash

Question 41

In authentication in a cryptographic system, the supplicant sends ________ to the verifier.

A) a key
B) a response message
C) credentials
D) a challenge message

Question 42

When ________ is applied to a binary message, the results is far shorter than the original message.

A) hashing
B) credentialing
C) verifying
D) keying

Question 43

Which of the following is FALSE about hashing?

A) It is irreversible.
B) It is repeatable.
C) It is an important part of how cryptographic systems function.
D) It produces ciphertext that is about as long as the plaintext that was sent.

Question 44

MS-CHAP is part of the ________.

A) Microsoft Windows Server operating system
B) Microsoft Windows PC operating system
C) Microsoft Office suite
D) Microsoft and Apple operating systems

Question 45

MS-CHAP is an encryption method.

Question 46

Unlike encryption, hashing is irreversible.

Question 47

One hashing method that is archaic and was primarily used in the past is MD5.

Question 48

SHA-2 is the hashing method that is recommended by NIST.

Question 49

Which are the two widely used public key encryption ciphers?

A) RSA and ECC
B) ECC and DES
C) RSA and AES
D) DES and 3DES

Question 50

Which of the following is FALSE about public key encryption ciphers?

A) They are extremely complex.
B) They are slow.
C) They are expensive to use.
D) They are often used to encrypt very long messages for confidentiality.

Question 51

For RSA public key encryption, a recommended minimum key length for a strong key is ________.

A) 1,024 bits
B) 256 bits
C) 1,024 bytes
D) 256 bytes

Question 52

Diffie-Hellman is a(n) ________.

A) authentication method
B) hashing method
C) popular keying method
D) communication method

Question 53

Symmetric key encryption is somewhat slow yet fairly expensive.

Question 54

Public key encryption and symmetric key encryption are complementary.

Question 55

Public key encryption takes 100 to 1,000 times longer than symmetric key encryption to encrypt a message of a given length.

Question 56

The use of public key encryption to do keying is widespread.

Question 57

Public key encryption to do keying is extremely vast.

Question 58

After two parties exchange session keys, what happens?

A) The two sides begin sending messages back and forth.
B) Encryption and decryption occurs.
C) The two sides begin the authentication phase.
D) Keying starts.

Question 59

A(n) ________ is when an attacker intercepts messages being sent between two parties and forwards them on.

A) replay attack
B) security through obscurity attack
C) evil twin attack
D) man-in-the-middle attack

Question 60

A(n) ________ occurs when an attacker intercepts an encrypted message and transmits it again later.

A) replay attack
B) security through obscurity attack
C) evil twin attack
D) man-in-the-middle attack

Question 61

An electronic signature provides ________ and ________.

A) authentication; handshaking
B) authentication; message integrity
C) handshaking; message integrity
D) keying; encryption

Question 62

A ________ is the person a supplicant claims to be.

A) verifier
B) public key
C) true party
D) digital signature

Question 63

A ________ authenticates a single message with public key encryption.

A) public key
B) verification
C) digital signature
D) message digest

Question 64

________ is an independent and trusted source of information about public keys of true parties.

A) A message digest
B) Verification
C) A digital signature
D) A certificate authority

Question 65

What are IdenTrust, Sectifo, and GoDaddy?

A) Certificate authorities
B) Verification authorities
C) Digital signature authorities
D) Message digest software suppliers

Question 66

________ uses a key exchanged during the initial negotiation phase.

A) A DES
B) The HMAC
C) A hash
D) A message digest

Question 67

Digital signatures are used much more often than are HMACs.

Question 68

The first step in creating a digital signature for authentication is to hash the plaintext message.

Question 69

If a send is the true party, the sender will be authenticated.

Question 70

If a message has changed while in transit, the message digests will match but will show a separate log of the changes.

Question 71

Digital certificates and digital signatures must be used together in public key authentication.

Question 72

Nonrepudiation means that a sender cannot deny that he or she sent an important message.

Question 73

Quantum mechanics governs ________.

A) national security
B) large-scale interactions
C) small-scale interactions
D) global security issues

Question 74

________ can deliver very long keys to communication partners.

A) Diffie-Hellman key exchange
B) Public key encryption
C) One-time key exchange
D) Quantum key distribution

Question 75

________ can be used to crack keys quickly by trying dozens or even thousands of keys at once.

A) Diffie-Hellman key exchange
B) Quantum key cracking
C) Public key encryption
D) One-time key exchange

Question 76

Quantum key distribution creates a one-time key.

Question 77

Currently, quantum computer can crack keys that are thousands of bits long.

Question 78

What is the first task in establishing a cryptographic system?

A) For a company to invent their own custom cryptographic protections
B) Selecting a cryptographic system standard for the dialogue
C) Handshaking tasks are performed
D) Verification takes place

Question 79

A ________connects a single client over an untrusted network to a single server.

A) host-to-host VPN
B) remote access VPN
C) one-time key
D) site-to-site VPN

Question 80

Cryptographic systems are nearly always used over trusted networks.