CHAPTER 9 / PUBLIC-KEY CRYPTOGRAPHY AND RSA

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

false

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

false

Asymmetric encryption transforms plaintext into ciphertext.

true

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

false

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

true

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

false

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

true

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

True

The encryption algorithm performs various transformation on the ciphertext.

false

If the authenticator is encrypted with the sender's private key, it serves as a signature that verifies origin, content, and sequencing.

true

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.

true

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

false

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

true

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

true

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

false

Asymmetric encryption is also known as ___ .

Public-key encryption

Public-key encryption is also known as ___ .

asymmetrical encryption

Asymmetric encryption can be used for __ .

both confidentiality and authentication

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

decryption algorithm

The most widely used public-key cryptosystem is __ .

RSA

Public-key algorithms are based on __ .

mathematical functions

__ 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.

asymmetric keys

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

Public Key Certificate

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.

Public Key (Asymmetric) Cryptographic Algorithm

A public-key encryption scheme has __ ingredients.

six

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

secret

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

plaintext

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

key generation

__ depend on the running time of the decryption algorithm.

timing attacks

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

time complexity

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

Asymmetric

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

key exchange

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

ciphertext

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

RSA

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

symmetric

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.

public key certificate

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.

Public Key Infrastructure (PKI)

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

Ciphertext

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.

trap door one-way function

"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 ___ .

digital signature

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

RSA

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.

Euclid

Five possible approaches to attacking the RSA algorithm are: brute force, mathematical attacks, hardware fault-based attacks, chosen ciphertext attacks, and ___.

timing attacks

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.

chosen ciphertext attack

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

optimal asymmetric encryption padding (OAEP)