CBCP Cryptography and Security 4

Question 1

What is the Schnorr signature scheme's key advantage over ECDSA in blockchain contexts?

Accepted Answer

It natively supports signature aggregation, allowing multiple signatures to be combined into one

Answer

Schnorr signatures support linear aggregation (e.g., MuSig), enabling multiple signers to produce a single compact signature, improving scalability and privacy.

Question 2

In symmetric encryption used for blockchain data at rest, what is the fundamental limitation compared to asymmetric encryption?

Accepted Answer

It requires a secure channel to share the secret key between parties

Answer

Symmetric encryption requires both parties to already share a secret key, making initial key exchange the central security challenge.

Question 3

What is a Pedersen commitment, and where is it commonly used in blockchain privacy?

Accepted Answer

A homomorphic commitment scheme allowing arithmetic on hidden values, used in confidential transactions

Answer

Pedersen commitments are computationally hiding and perfectly binding; their homomorphic property allows verifying transaction balance without revealing amounts, as in Confidential Transactions.

Question 4

What does 'perfect forward secrecy' (PFS) mean in the context of blockchain node communications?

Accepted Answer

Past session keys cannot be compromised even if the long-term private key is later revealed

Answer

PFS ensures that session keys derived from ephemeral key exchanges remain secure even if the server's long-term private key is later compromised.

Question 5

How does a ring signature in Monero provide sender anonymity?

Accepted Answer

It allows a signer to sign on behalf of a group without revealing which group member actually signed

Answer

Ring signatures let one member of a group (ring) sign a message such that any ring member could plausibly be the signer, providing sender ambiguity.

CBCP - Certified Blockchain Professional Practice Test

CBCP - Certified Blockchain Professional Practice Test

CBCP Cryptography and Security 4