Week 6- Principles of cryptography: fundamentals and symmetric systems

Question 1

What is Cryptology?

Answer 1

the science of secure communications

Question 2

what is cryptanalysis?

Answer 2

the study of encryption to detect vulnerabilities and propose cryptographic techniques.

Question 3

what is cryptography?

Answer 3

encode and decode information for secure communication.

achieves confidentiality and integrity of CIA triad.

Question 4

what is a block cipher?

Answer 4

a cryptographic method, data is broken into smaller blocks for encryption and decryption using a cryptographic key

Question 5

what is a cryptographic key?

Answer 5

a numerical value that act as an input to encryption/decryption algorithm.

Question 6

what is AES?

Answer 6

advanced encryption standard.

symmetric block cypher used across the internet and wi-fi networks.

Question 7

Define Diffie-Hellman (DH)

Answer 7

a key exchange, mathematical algorithm whereby two entities can share a symmetric key remotely.

Question 8

what does Moore’s law predict?

Answer 8

that computer power and its ability to crack a code doubles every 18 months.

Question 9

define brute-force-attack

Answer 9

an exhaustive cryptanalytic method, attempts every possible key/password combination until on works.

Question 10

what is 3DES?

Answer 10

3 digital encryption standard

symmetric block cipher with key length 112 or 168 bits.

Question 11

Define reverse engineering

Answer 11

using the output of a device/system to figure out how it works

Question 12

What is a dictionary attack?

Answer 12

an attempt to break into a password protected system by using a list of well-known words or phrases.

Question 13

define digital signature

Answer 13

authenticating the authorship of a message

Question 14

define digital certificate

Answer 14

proof of ownership of a public key

Question 15

define public key

Answer 15

asymmetrical cryptographic key available to anyone

Question 16

Define web of trust

Answer 16

an arrangement of entities where there is a relationship of trust

Question 17

define plaintext

Answer 17

unencrypted information

Question 18

define ciphertext

Answer 18

encrypted information

Question 19

define a cipher or cryptographic algorithm

Answer 19

mathematics responsible for turning plaintext to ciphertext or reverting it back plaintext

Question 20

define encryption

Answer 20

the process of converting plaintext to ciphertext

Question 21

define cryptographic key

Answer 21

a numerical value with a string of bits of specific size used to encrypt or decrypt

Question 22

define encryption key

Answer 22

a cryptographic key, a piece of information used with an algorithm (cipher) to turn plaintext to ciphertext

(decryption key does the opposite)

Question 23

define symmetric cryptography

Answer 23

encryption and decryption use the same cryptographic key

Question 24

define asymmetric cryptography

Answer 24

encryption and decryption use different keys

Question 25

define decryption

Answer 25

the act of taking a encrypted message and rendering it readable

Question 26

ciphers can be categorised into 2 types, what are they?

Answer 26

**block cipher** divides plaintext into fixed lengths of bits (3DES) **stream cipher** a symmetric method, bits are encrypted one at a time for streaming audio/video

Question 27

define initialisation vector

Answer 27

the value required in the generation of a block or stream cipher, should not be easily predicted

Question 28

what is CSPRNG

Answer 28

cryptographically secure pseudo random number generator an algorithm that produces random numbers, may rely on environmental changes

Question 29

what is stenography

Answer 29

The study of hiding information inside other information – often in a picture or audio file.