CBCP Cryptography 4

Question 1

What is the BIP-39 standard primarily used for in cryptocurrency wallets?

Accepted Answer

Encoding a wallet seed as a human-readable mnemonic phrase

Answer

BIP-39 defines how to encode 128-256 bits of entropy as a 12-24 word mnemonic phrase from a fixed wordlist, making wallet backup human-friendly.

Question 2

What is the key difference between ZK-SNARKs and ZK-STARKs?

Accepted Answer

STARKs do not require a trusted setup ceremony and are quantum-resistant

Answer

ZK-STARKs rely only on hash functions (making them quantum-resistant) and require no trusted setup, unlike ZK-SNARKs which need a trusted ceremony and use elliptic curve pairings.

Question 3

In the context of public-key cryptography, what does 'key encapsulation' accomplish?

Accepted Answer

It wraps a symmetric key inside an asymmetric encryption operation for secure transmission

Answer

Key encapsulation mechanisms (KEMs) use asymmetric cryptography to securely transmit a symmetric session key, which then encrypts the actual data more efficiently.

Question 4

Which attack exploits the birthday paradox to find hash collisions more efficiently than brute force?

Accepted Answer

Birthday attack

Answer

A birthday attack exploits the birthday paradox: finding any two inputs with the same hash requires only approximately √(2^n) operations rather than 2^n, halving the effective security bits.

Question 5

What property does a cryptographic accumulator provide that a Merkle tree also provides?

Accepted Answer

Compact membership proofs for elements in a set

Answer

Both cryptographic accumulators and Merkle trees enable compact proofs of membership (and sometimes non-membership) for elements in a large set.

CBCP - Certified Blockchain Professional Practice Test

CBCP - Certified Blockchain Professional Practice Test

CBCP Cryptography 4