Chapter 5: Cryptography

Question 1

involves shifting each letter of the plaintext message by a certain number of letters

Answer 1

Caesar cipher

Question 2

the science of keeping information secure

Answer 2

cryptography

Question 3

mechanical cryptographic device invented in 1795 composed by a series of disks each marked with the letters a to z around its edge

Answer 3

The Jefferson Disk (by Thomas Jefferson)

Question 4

created by Arthur Scherbius in 1923 used to secure German communication during World War II.

Answer 4

Enigma

Question 5

tenet of cryptographic algorithms

Answer 5

The system must not require secrecy and can be stolen by the enemy without causing trouble/ the enemy knows the system (Claude Shannon)

Question 6

uses a single key for both encryption of the plaintext and decryption of ciphertext

Answer 6

symmetric cryptography

Question 7

takes a predetermined number of bits known as a block in the plaintext message and encrypts that block

Answer 7

block ciphers

Question 8

a block cipher based on symmetric key cryptography and uses a 56-bit key. (1976)

Answer 8

DES (Data Encryption Standard)

Question 9

uses DES 3 times

Answer 9

3DES

Question 10

uses three different cipher: 128 bit key, 192 bit key, one 256 bit key

Answer 10

AES

Question 11

uses two keys

Answer 11

asymmetric cryptography

Question 12

an asymmetric algorithm used all over the world and SSL

Answer 12

RSA algorithm