Cryptography

Question 1

What does the private key of an account act as?

Answer 1

The private key of an account acts as the password for that account.

Question 2

What can a person do if they have access to the private key of an account?

Answer 2

1. Send/sign transactions
2. Access the funds associated with that account

Question 3

Should private keys be shared online or with other people?

Answer 3

No, private keys should never be shared online or with other people.

Question 4

Where should private keys be stored?

Answer 4

1. Private keys should be stored in a secure location
2. Private keys should be stored in multiple secure locations

Question 5

Can you retrieve your funds if your private key is lost or stolen?

Answer 5

1. No, if your private key is lost or stolen, you cannot retrieve your funds as the private key acts as the password to your account.
2. The public key is also needed

Question 6

Can you change your private key if it is compromised?

Answer 6

No, you cannot change your private key. If it is compromised, you would have to move your funds to a new account with a new private key.

Question 7

What is a public key in the context of a blockchain account?

Answer 7

1. A blockchain account’s public key acts as the identifier for an account.
2. Public keys and addresses are derived from private keys using algorithms like elliptic curve multiplication or RSA

Question 8

What role do nodes on a network play in relation to a public key?

Answer 8

Nodes on a network can validate transactions that were signed properly using an account’s public key.

Question 9

Is it safe to share your public key?

Answer 9

Yes, it is safe to share your public key.

Question 10

How is a public key derived?

Answer 10

A public key is derived from a private key.

Question 11

How is a public key different from an address?

Answer 11

1. A public key is a longer form of an address.
2. Less convenient form of an address.

Question 12

An Ethereum address is how many bytes?

Answer 12

20 bytes (160 bits or 40 hex characters)

Question 13

How is a address different from an public key?

Answer 13

1. A address is a shorter and
2. More convenient form of an address

Question 14

What are hash functions in the context of internet security and cryptography?

Answer 14

1. Hash functions are “one-way” functions that have no known inverse.
2. They are the foundation of modern internet security and cryptography.

Question 15

How is the speed of computing hash functions?

Answer 15

Hash functions are fast to compute.

Question 16

What is a hash function digest?

Answer 16

Hash functions generate a uniform output, also known as a digest.

Question 17

What does it mean when we say hash functions are deterministic?

Answer 17

Hash functions are deterministic, which means given the same input, they will always produce the same output.

Question 18

What is a hash collision and how common is it?

Answer 18

A hash collision occurs when two different inputs produce the same output hash. However, this is very rare with good hash functions.

Question 19

List the properties of a hash function?

Answer 19

1. Fast to compute.
2. Generate a uniform output (a.k.a digest, e.g. same length).
3. No known inverse.
4. Deterministic.
5. Very rare hash collisions.

Question 20

What size is a size is a private key?

Answer 20

64-digit hexadecimal strings (valid characters are 0 - 9 and a - f)

Question 21

What are private keys encrypted with?

Answer 21

Private keys are typically encrypted with a password.