Cryptographic Principles Flashcards
7 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Cryptographic Principles flashcards as text
Which hashing algorithm does Bitcoin use to produce block header hashes during proof-of-work mining?
Answer: SHA-256 (applied twice)
Bitcoin applies SHA-256 twice (SHA-256d) to compute the block header hash used in proof-of-work.
In the secp256k1 curve used by Bitcoin, what is the typical size of an uncompressed public key?
Answer: 65 bytes
An uncompressed secp256k1 public key is 65 bytes: a 0x04 prefix followed by two 32-byte coordinates (x and y).
What cryptographic operation converts a Bitcoin public key into a Bitcoin address?
Answer: SHA-256 then RIPEMD-160, followed by Base58Check encoding
Bitcoin addresses are derived by hashing the public key with SHA-256 then RIPEMD-160, and encoding the result with Base58Check.
Which property ensures that a small change in input produces a drastically different hash output, making hash outputs unpredictable?
Answer: The avalanche effect
The avalanche effect means that flipping even a single bit in the input causes approximately half the output bits to change.
In asymmetric cryptography, if Alice wants to send Bob a confidential message, which key does she use to encrypt it?
Answer: Bob's public key
Alice encrypts with Bob's public key so that only Bob, holding the corresponding private key, can decrypt the message.
What is the primary advantage of using elliptic curve cryptography (ECC) over RSA for blockchain applications?
Answer: ECC achieves equivalent security with much shorter key sizes
A 256-bit ECC key provides roughly the same security as a 3072-bit RSA key, significantly reducing storage and bandwidth overhead.
In Ethereum, which hashing function is used to compute the Keccak hash of transactions and state roots?
Answer: Keccak-256 (SHA-3 variant)
Ethereum uses Keccak-256, a variant of SHA-3, for hashing transactions, addresses, and state trie nodes.