CBP Fundamental Cryptography Concepts 2

Question 1

Which mathematical property makes elliptic curve cryptography secure for Bitcoin key generation?

Accepted Answer

The discrete logarithm problem on elliptic curves is computationally infeasible to reverse

Answer

Elliptic curves produce keys that are immune to brute-force attacks of any length

Answer

Elliptic curve arithmetic operates in base-58 which computers cannot process

Answer

The curve equation guarantees that private keys are always prime numbers

Question 2

What does it mean for a hash function to be 'collision-resistant'?

Accepted Answer

It is computationally infeasible to find two different inputs that produce the same hash output

Answer

The hash function never produces the same output twice for any input

Answer

Collision resistance means the hash output length never changes

Answer

It means the function cannot be run more than once on the same data

Question 3

In Bitcoin's Merkle tree, what is the Merkle root used for?

Accepted Answer

To summarize all transactions in a block into a single hash for efficient verification

Answer

To store the private keys of all transaction senders in a block

Answer

To generate new Bitcoin addresses for miners as a reward

Answer

To encrypt the block header before broadcasting to the network

Question 4

What is the purpose of a nonce in Bitcoin's proof-of-work mining?

Accepted Answer

Miners vary the nonce to find a block hash that meets the network difficulty target

Answer

The nonce is a unique identifier assigned to each Bitcoin address

Answer

It is a random number embedded in each transaction to prevent double-spending

Answer

The nonce encrypts the coinbase transaction before inclusion in the block

Question 5

Which of the following best describes a 'preimage attack' on a hash function?

Accepted Answer

Finding an input that hashes to a given target output

Answer

Generating two inputs with identical hash outputs

Answer

Reversing the hash function algebraically to recover plaintext

Answer

Modifying a hashed message without changing its hash value

Question 6

How does asymmetric cryptography differ from symmetric cryptography in Bitcoin's context?

Accepted Answer

Asymmetric uses a public/private key pair while symmetric uses one shared secret key

Answer

Asymmetric encryption is faster but less secure than symmetric encryption

Answer

Symmetric cryptography uses two different keys while asymmetric uses one key for all operations

Answer

Bitcoin exclusively uses symmetric cryptography for all transaction signing

Question 7

What property ensures that a digital signature can only be created by the holder of the private key?

Accepted Answer

Unforgeability — it is computationally infeasible to produce a valid signature without the private key

Answer

The private key is embedded inside every signature so nodes can verify ownership

Answer

Only the Bitcoin network can generate signatures by validating transactions in real time

Answer

Signatures are created by hashing the public key, which only the owner can access