Week 1 : Course Introduction

Question 1

Cryptography

Answer 1

is a method of storing and transmitting data in a form that only those it is intended for can read and process.

Question 2

Cryptography

Answer 2

A science of protecting information by encoding it into an unreadable format.

Question 3

What i the ultimate goal of cryptography

Answer 3

The ultimate goal of cryptography is to hide information from unauthorized individuals,

A more realistic goal of cryptography is to make obtaining the information too work-intensive to be worth it to the attacker.

Question 4

Today’s transmission mechanism of encrypted message

Answer 4

packets carrying 0’s and 1’s passing through network cables or open airwaves

Question 5

What is atbash

.

Answer 5

Encryption method requiring the alphabet to be flipped so that each letter in the original alphabet is mapped to a different letter in the flipped alphabet

Question 6

Cryptanalysis

Answer 6

is a science of studying and breaking the secrecy of encryption algorithms and their necessary pieces.

Question 7

What is encryption?

Answer 7

Encryption is a method of transforming original data, called plaintext or cleartext, into a form that appears to be random and unreadable, which is called ciphertext.

Question 8

what is cryptosystem

Answer 8

A system that provides encryption and decryption

Question 9

what is keyspace

Answer 9

range of values that can be used to construct a key

Question 10

What is work factor?

Answer 10

Is an estimate of the effort it would take an attacker to penetrate an encryption method.

Question 11

What can Cryptosystems provide

Answer 11

Cryptosystems can provide confidentiality, authenticity, integrity, and nonrepudiation services.

Question 12

Confidentiality

Answer 12

means that unauthorized parties cannot access information.

Question 13

Authenticity

Answer 13

refers to validating the source of the message to ensure the sender is properly identified.

Question 14

Integrity

Answer 14

provides assurance that the message was not modified during transmission, accidentally or intentionally.

Question 15

Nonrepudiation

Answer 15

means that a sender cannot deny sending the message at a later date, and the receiver cannot deny receiving it

Question 16

Cryptology

Answer 16

The study of both cryptography and cryptanalysis

Question 17

Ciphertext

Answer 17

Data in encrypted or unreadable format

Question 18

Encipher

Answer 18

Act of transforming data into an unreadable format

Question 19

Decipher

Answer 19

Act of transforming data into a readable format

Question 20

Key

Answer 20

Secret sequence of bits and instructions that governs the act of encryption and decryption

Question 21

Key clustering

Answer 21

Instance when two different keys generate the same ciphertext from the same plaintext

Question 22

Keyspace

Answer 22

Possible values used to construct keys

Question 23

Plaintext

Answer 23

Data in readable format, also referred to as cleartext

Question 24

Cryptography history

Answer 24

has roots that began around 2000 BC in Egypt when hieroglyphics were used to decorate tombs to tell the story of the life of the deceased.

Question 25

When was the first system of encrypting information

Answer 25

Around 400 BC, the Spartans used a system of encrypting information by writing a message on a sheet of papyrus, which was wrapped around a staff.

Question 26

Algorithm

Answer 26

Set of mathematical rules used in encryption and decryption

Question 27

Breaking a key

Answer 27

has to do with processing an amazing

number of possible values in the hopes of finding the one value that can be used to decrypt a specific message

Question 28

When was the first encryption?

Answer 28

Dated back to 4000 years ago

Question 29

what is a packet?

Answer 29

A transmission mechanism

Question 30

Root of Cryptography

Answer 30

Aroud 2000 DC

Question 31

The rotor cipher machine,

Answer 31

Called Enigma, device that substitutes letters using different rotors within the machine

Question 32

Who is the father of Cryptographie

Answer 32

William Friedman

Question 33

Clipper Chip

Answer 33

Encryption method developed by law enforcement

Question 34

The strength of the encryption method

Answer 34

comes from the algorithm, secrecy of the key,length of the key, initialization vectors, and how they all work together.

When strength is discussed in encryption, it refers to how hard it is to figure out the algorithm or key,
whichever is not made public.

Question 35

brute force attack,

Answer 35

means trying every possible key value until the resulting plaintext is meaningful.