lecture 5

Question 2

What is Cryptography?

Answer 2

Cryptography is scrambling information so it cannot be read and transforms information into a secure form so unauthorised persons cannot access it

Question 3

What is Steganography?

Answer 3

Steganography hides the existence of data by embedding hidden messages in images audio or video files

Question 4

How is data hidden using Steganography?

Answer 4

Data is divided and hidden in unused portions of the file or in file header fields between metadata sections

Question 5

What is Encryption?

Answer 5

Encryption is changing original text into a secret message using cryptography

Question 6

What is Decryption?

Answer 6

Decryption is changing the secret message back to its original form

Question 7

What is Plaintext?

Answer 7

Plaintext is unencrypted data to be encrypted or the output of decryption

Question 8

What is Ciphertext?

Answer 8

Ciphertext is the scrambled and unreadable output of encryption

Question 9

What is Cleartext?

Answer 9

Cleartext data is data stored or transmitted without encryption

Question 10

What does a Cryptographic Algorithm do?

Answer 10

A cryptographic algorithm uses mathematical formulas to encrypt and decrypt data

Question 11

What is a Key in cryptography?

Answer 11

A key is a mathematical value entered into the algorithm to produce ciphertext and is used in reverse to decrypt

Question 12

What is a Substitution Cipher?

Answer 12

A substitution cipher replaces one character with another

Question 13

What is ROT13?

Answer 13

ROT13 is a substitution cipher where the alphabet is rotated 13 steps such that A becomes N

Question 14

What is an XOR cipher?

Answer 14

An XOR cipher uses the binary operation eXclusive OR to compare bits returning 1 if bits differ and 0 if identical

Question 15

What protections can Cryptography provide?

Answer 15

Confidentiality integrity authentication nonrepudiation and obfuscation

Question 16

What is Confidentiality in cryptography?

Answer 16

Confidentiality ensures only authorised parties can view the information

Question 17

What is Integrity in cryptography?

Answer 17

Integrity ensures that information is correct and unaltered

Question 18

What is Authentication in cryptography?

Answer 18

Authentication verifies the sender through cryptography

Question 19

What is Nonrepudiation?

Answer 19

Nonrepudiation proves that a user performed an action and cannot deny it

Question 20

What is Obfuscation?

Answer 20

Obfuscation is making something obscure or unclear often used as security through obscurity

Question 21

What are the three states of data Cryptography protects?

Answer 21

Data in processing data in transit and data at rest

Question 22

What is a limitation of Cryptography related to low-power devices?

Answer 22

Low-power devices require protection but have limited resources restricting strong cryptography use

Question 23

What is the Resource vs Security Constraint?

Answer 23

It is the balance between available resources like time and energy and the security level provided by cryptography

Question 24

What are the three categories of Cryptographic Algorithms?

Answer 24

Hash algorithms symmetric cryptographic algorithms and asymmetric cryptographic algorithms

Question 25

What does a Hash Algorithm do?

Answer 25

A hash algorithm creates a unique digital fingerprint called a digest representing the contents of data

Question 26

What are characteristics of a Secure Hash?

Answer 26

Fixed size unique original and secure meaning the hash cannot be reversed to find original data

Question 27

What is Symmetric Cryptography?

Answer 27

Symmetric cryptography uses the same single key to encrypt and decrypt data also called private key cryptography

Question 28

Name some common Symmetric Algorithms.

Answer 28

DES 3DES AES RC Blowfish

Question 29

What is the primary weakness of Symmetric Cryptography?

Answer 29

The difficulty in securely distributing and maintaining a single key among multiple users

Question 30

What is Asymmetric Cryptography?

Answer 30

Asymmetric cryptography uses two mathematically related keys a public key and a private key

Question 31

What is a Public Key?

Answer 31

A public key is available to everyone and freely distributed

Question 32

What is a Private Key?

Answer 32

A private key is known only to its owner and kept secret

Question 33

Name some Asymmetric Cryptographic Algorithms.

Answer 33

RSA ECC DSA Diffie-Hellman

Question 34

What is RSA based on?

Answer 34

RSA is based on multiplying two large prime numbers and the security relies on factoring

Question 35

What is Elliptic Curve Cryptography (ECC)?

Answer 35

ECC uses elliptic curves and smaller keys requiring less computing power often used for mobile devices

Question 36

What is a Digital Signature?

Answer 36

A digital signature is an electronic verification of the sender ensuring authenticity and integrity

Question 37

What is the purpose of Key Exchange protocols?

Answer 37

To securely share cryptographic keys within normal communication channels

Question 38

Name some Key Exchange protocols.

Answer 38

Diffie-Hellman Diffie-Hellman Ephemeral Elliptic Curve Diffie-Hellman Perfect forward secrecy

Question 39

What are common Cryptographic Attacks?

Answer 39

Algorithm attacks and collision attacks

Question 40

What is an Algorithm Attack?

Answer 40

An attack using methods like known ciphertext attacks downgrade attacks or exploiting misconfigurations to bypass strong algorithms

Question 41

What is a Collision Attack?

Answer 41

An attack that tries to find two inputs producing the same hash causing a hash collision

Question 42

What is a Birthday Attack?

Answer 42

A collision attack based on the birthday paradox estimating probability of two inputs having the same hash

Question 43

What is Quantum Cryptography?

Answer 43

Quantum cryptography uses quantum computing principles to enhance cybersecurity and detect eavesdroppers

Question 44

What is a major risk of Quantum Computing for Cryptography?

Answer 44

Quantum computers could quickly factor large numbers breaking current asymmetric cryptographic algorithms

Question 45

How can Cryptography be applied?

Answer 45

Cryptography can be applied through software or hardware

Question 46

What is Full Disk Encryption (FDE)?

Answer 46

FDE encrypts the entire hard drive preventing unauthorized data access even if the drive is moved

Question 47

What is a Trusted Platform Module (TPM)?

Answer 47

A TPM is a hardware chip on a motherboard providing cryptographic services and protection against software attacks

Question 48

What are Self-Encrypting Drives (SEDs)?

Answer 48

SEDs are hard drives that encrypt all data stored on them and authenticate the host device on power-up

Question 49

What is Blockchain?

Answer 49

Blockchain is a shared immutable ledger recording transactions across multiple computers using cryptographic hash algorithms