Chapter 4 - Basic Cryptography Concepts

Question 1

What is the practice and study of techniques to secure communication in the presence of third parties?

Answer 1

Cryptography

Question 2

What is the practice and study of determining and exploiting weakness in cryptographic techniques?

Answer 2

Cryptanalysis

Question 3

Ensuring that only authorized parties can read a message

Answer 3

Confidentiality

Question 4

Ensuring that any changes to data in transit will be detected and rejected

Answer 4

Data Integrity

Question 5

Ensuring that any messages received were actually sent from the perceived origin

Answer 5

Origin Authentication

Question 6

Ensuring that the original source of a secured message cannot deny having produced the message

Answer 6

Non-repudiation

Question 7

An algorithm for performing encryption and decryption

Answer 7

Cipher

Question 8

A cipher that substitutes one letter for another and retains the letter frequency of the original message

Answer 8

Substitution Cipher

Question 9

A cipher based on substitution that uses multiple substitution alphabets

Answer 9

Polyalphabetic cipher

Question 10

A cipher that rearranges or permutates letters

Answer 10

Transposition Cipher

Question 11

A cipher also known as a Vernam cipher that is a stream cipher that applies the XOR operation to plaintext with a key

Answer 11

One-time pad

Question 12

A mechanism that uses one-way mathematical functions to assure data integrity

Answer 12

Hashing

Question 13

Three most common hash functions

Answer 13

MD5, SHA-1, and SHA-2

Question 14

The process of disguising a message in such a way as to hide its original contents

Answer 14

Encryption

Question 15

An attack where decryption is attempted using all possible keys

Answer 15

Brute-force

Question 16

The effect of changing only a few bits of plaintext causing ciphertext to change completely

Answer 16

Avalanche effect

Question 17

Encryption type that uses the same key to encrypt and decrypt data

Answer 17

Symmetric encryption algorithm

Question 18

Encryption type that uses different keys to encrypt and decrypt data

Answer 18

Asymmetric encryption algorithm

Question 19

The practice of breaking codes to obtain the meaning of encrypted data

Answer 19

Cryptanalysis

Question 20

An attack where the attacker has only the ciphertext of messages encrypted using the same algorithm with no knowledge of the hidden plain text

Answer 20

Ciphertext-only attack

Question 21

An attack where the attacker has access to the ciphertext of seversal messages, but also knows something about the plain text

Answer 21

Known-plaintext attack

Question 22

An attack where the attacker chooses what data the encryption device encrypts and observes the ciphertext output

Answer 22

Chosen-plaintext attack

Question 23

An attack where the attacker can choose different ciphertext to be decrypted and has access to the decrypted plaintext

Answer 23

Chosen-ciphertext attack

Question 24

A brute-force style attack against hash functions where random input returns one of k equally likely values then by repeating the function with different inputs

Answer 24

Birthday attack

Question 25

An attack where the attacker knows a portion of the plaintext and the corresponding ciphertext

Answer 25

Meet-in-the-middle attack

Question 26

Widely used symmetric encryption algorithms

Answer 26

DES, 3DES, AES, RC4

Question 27

Common asymmetric encryption algorithms

Answer 27

RSA, DSA, EIGamal, and elliptic curve algorithms

Question 28

Method that allows two parties to share information over an untrusted network and mutually compute an identical shared secret that cannot be computed by eavesdroppers

Answer 28

Diffie-Hellman key agreement