Week 2 - Hashing

Question 1

What is a hash (hash function)?

Answer 1

Any data length is fed into a hash function, the output is always the same fixed length but always different from the input

Question 2

How is cryptographic hashing different from encryption?

Answer 2

Cryptographic hash functions should be one-directional and can’t recover the plaintext from output like encryption does

Question 3

Cryptographic hash functions are very similar to ___ key block ciphers

Answer 3

symmetric (because they operate on blocks of data)

Question 4

___ is more secure than MD5 hash function

Answer 4

SHA1 hash

Question 5

What does MIC stand for?

Answer 5

Message Integrity Check

Question 6

What does a MIC do?

Answer 6

it’s essentially a check sum for a message, ensures contents were modified in transit

Question 7

How is a MIC different from a MAC from a previous lesson?

Answer 7

MIC doesn’t use secret keys, has no authentication (doesn’t protect against tampering or malicious actions)

Question 8

What does MIC protect against?

Answer 8

accidental corruption/loss

Question 9

What’s one crucial application for cryptographic hash functions?

Answer 9

authentication

Question 10

What should you do instead of storing a plaintext file of your password?

Answer 10

store a hash of the password instead of the password itself (like what every authentication system does)

Question 11

T or F: If an attacker has unlimited time and/or resources, any system can be brute forced

Answer 11

True (impossible to protect against completely)

Question 12

What are 2 ways to protect against brute force attacks?

Answer 12

1. Make it sufficiently time-consuming and resource-intensive so it’s not practical with useful tech or a useful time frame
2. Run the password through the hashing function multiple times (sometimes thousands of times)

Question 13

What are rainbow tables used for?

Answer 13

used to help speed up the process of recovering passwords from stolen password hashes

Question 14

How are using rainbow tables different from a brute force attack?

Answer 14

rainbow tables store all possible password values and their hashes, whereas a brute force attack computes each guess attempt

Question 15

How do you protect against rainbow tables?

Answer 15

password salt (additional data gibberish to make password and salt combo unique) and to make it more time/resource consuming to compute