Cryptography and Hashing Flashcards
7 cards from real Cryptocurrency practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Cryptography and Hashing flashcards as text
What is a 'ring signature' used for in privacy-focused cryptocurrencies like Monero?
Answer: To allow a user to sign a transaction on behalf of a group without revealing which member signed
Ring signatures let a signer produce a signature verifiable as coming from a group while hiding which specific group member actually signed.
What is the primary purpose of the ECDSA (Elliptic Curve Digital Signature Algorithm) in Bitcoin?
Answer: To generate and verify transaction signatures proving ownership of funds
ECDSA is used to create digital signatures for Bitcoin transactions, allowing nodes to verify the sender owns the referenced UTXOs.
What is 'replay protection' in the context of cryptographic transaction signing during a blockchain hard fork?
Answer: A mechanism ensuring a signed transaction on one chain cannot be rebroadcast on a forked chain
Replay protection modifies transaction signing to include chain-specific data, so a valid transaction on one fork is invalid on the other.
What distinguishes a 'trapdoor function' from a regular one-way function in public-key cryptography?
Answer: A trapdoor function can be reversed only with a special secret (private key)
A trapdoor function is easy to compute forward and hard to reverse, except for someone who knows the secret trapdoor — the private key.
What is the 'difficulty target' in Bitcoin mining, and how does hashing relate to it?
Answer: A threshold the block's SHA-256 hash must be numerically below to be accepted
Miners must find a nonce such that the block header's double SHA-256 hash is less than the current difficulty target, a number with many leading zeros.
In Schnorr signatures (used in Bitcoin's Taproot upgrade), what key advantage do they offer over ECDSA?
Answer: They are linearly aggregatable, allowing multiple signatures to be combined into one
Schnorr signatures support linear aggregation, so a multi-signature transaction can present a single aggregated signature indistinguishable from a single-signer one.
What is a 'stealth address' in cryptocurrency privacy, and which cryptographic concept enables it?
Answer: A one-time address generated per transaction using Diffie-Hellman key exchange so only the recipient can detect it
Stealth addresses use ECDH (Elliptic Curve Diffie-Hellman) to let a sender generate a one-time address only the intended recipient's private key can detect and spend from.