Deck 9: Public-Key Cryptography and Rsa

Question 1

Asymmetric encryption transforms plaintext into ciphertext.

Answer 1

True

Question 2

Asymmetric encryption utilizes only a public key for encryption and decryption.

Answer 2

False

Question 3

A trap-door one-way function is easy to calculate in one direction and infeasible to calculate in the other direction unless certain additional information is known.

Answer 3

True

Question 4

Asymmetric encryption can be used for __________ .

A)both confidentiality and authentication
B)neither confidentiality nor authentication
C)confidentiality
D)authentication

Question 5

The encryption algorithm performs various transformation on the ciphertext.

Question 6

The defense against the brute-force approach for RSA is to use a large key space.

Question 7

A major advance in symmetric cryptography occurred with the development of the rotor encryption/decryption machine.

Question 8

The most widely used public-key cryptosystem is __________ .

A)optimal asymmetric encryption
B)asymmetric encryption
C)RSA
D)DES

Question 9

Plaintext is transformed into ciphertext using two keys and a decryption algorithm.

Question 10

Asymmetric encryption can be used for confidentiality but not for authentication.

Question 11

Before the application of the public-key cryptosystem each participant must generate a pair of keys.

Question 12

Timing attacks are ciphertext attacks that are only applicable to RSA.

Question 13

A public-key encryption scheme is not vulnerable to a brute-force attack.

Question 14

Public-key encryption is more secure from cryptanalysis than symmetric encryption.

Question 15

Plaintext is recovered from the ciphertext using the paired key and a _____________ .

A)digital signature
B)recovery encryption
C)decryption algorithm
D)encryption algorithm

Question 16

Public-key encryption is also known as ___________ .

A)digital-key encryption
B)asymmetric encryption
C)one way time exchange encryption
D)optimal-key encryption

Question 17

Asymmetric algorithms rely on one key for encryption and a different but related key for decryption.

Question 18

T F` 10.If the authenticator is encrypted with the sender's private key,it serves as a signature that verifies origin,content,and sequencing.

Question 19

Much of the theory of public-key cryptosystems is based on number theory.

Question 20

Asymmetric encryption is also known as ___________ .

A)public-key encryption
B)private-key encryption
C)optimal encryption
D)digital-key encryption

Question 21

A public-key encryption scheme has __________ ingredients.

A)six
B)four
C)eight
D)two

Question 22

Asymmetric encryption transforms plaintext into __________ using one of two keys and an encryption algorithm.

Question 23

The scrambled message produced as output is the __________ .It depends on the plaintext and the key.

Question 24

"The sender 'signs' a message with its private key.Signing is achieved by a cryptographic algorithm applied to the message or to a small block of data that is a function of the message," is a description of a ___________ .

Question 25

The readable message or data that is fed into the algorithm as input is the ____________ .

A)ciphertext
B)exchange
C)plaintext
D)encryption

Question 26

The key used in symmetric encryption is referred to as a __________ key.

A)public
B)secret
C)private
D)decryption

Question 27

Public-key algorithms are based on __________ .

A)permutation
B)mathematical functions
C)substitution
D)symmetry

Question 28

We define the ___________ of an algorithm to be fn)if,for all n and all inputs of length n the execution of the algorithm takes at most fn)steps.This is a common measure of the efficiency of an algorithm.

A)time complexity
B)one-way function
C)timing attack
D)OAEP

Question 29

__________ are two related keys,a public key and a private key that are used to perform complementary operations,such as encryption and decryption or signature generation and signature verification.

A)Asymmetric keys
B)Key exchanges
C)Symmetric keys
D)Cipher keys

Question 30

The __________ indicates that the subscriber identified in the certificate has sole control and access to the private key.

A)OAEP
B)Public Key Certificate
C)Digital Signature
D)PKI

Question 31

The difficulty of attacking __________ is based on the difficulty of finding the prime factors of a composite number.

Question 32

A __________ is a digital document issued and digitally signed by the private key of a Certification Authority that binds the name of a subscriber to a public key.

Question 33

A __________ is when two sides cooperate to exchange a session key.

Question 34

A __________ is a cryptographic algorithm that uses two related keys,a public key and a private key.The two keys have the property that deriving the private key from the public key is computationally infeasible.

A)Private Key Symmetric)Cryptographic Algorithm
B)Key Exchange Cryptographic Algorithm
C)Public Key Asymmetric)Cryptographic Algorithm
D)RSA Digital Cryptographic Algorithm

Question 35

Two issues to consider with the computation required to use RSA are encryption/decryption and __________ .

A)time complexity
B)trap-door one-way functions
C)key generation
D)asymmetric encryption padding

Question 36

__________ depend on the running time of the decryption algorithm.

A)Mathematical attacks
B)Timing attacks
C)Chosen ciphertext attacks
D)Brute-force attacks

Question 37

The __________ is a set of policies,processes,server platforms,software and workstations used for the purpose of administering certificates and public-private key pairs,including the ability to issue,maintain,and revoke public key certificates.

Question 38

__________ encryption is a form of cryptosystem in which encryption and decryption are performed using a public key and a private key.

Question 39

Public-key cryptography is asymmetric,involving the use of two separate keys,in contrast to ___________ encryption,which uses only one key.

Question 40

A __________ is one that maps a domain into a range such that every function value has a unique inverse,with the condition that the calculation of the function is easy,whereas the calculation of the inverse is infeasible.

Question 41

A single algorithm that will calculate the greatest common divisor gcd)of two integers and,if the gcd is 1,determine the inverse of one of the integers modulo the other,is the __________ algorithm.

Question 42

A __________ is an attack in which the adversary chooses a number of ciphertexts and is then given the corresponding plaintexts,decrypted with the target's private key.

Question 43

To counter attacks such as CCAs,RSA Security,Inc. recommends modifying the plaintext using a procedure known as ___________ .

Question 44

The __________ scheme is a block cipher in which the plaintext and ciphertext are integers between 0 and n - 1 for some n.

Question 45

Four possible approaches to attacking the RSA algorithm are: brute force,mathematical attacks,chosen ciphertext attacks,and ___________ .