Bitcoin Basics and Cryptography Flashcards
7 cards from real CBP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Bitcoin Basics and Cryptography flashcards as text
What is the 'difficulty adjustment' in Bitcoin and how often does it occur?
Answer: An automatic recalibration of mining difficulty every 2016 blocks (~2 weeks) to target 10-minute block intervals
Every 2016 blocks, Bitcoin nodes recalculate the difficulty target so that the average time between blocks remains approximately 10 minutes.
What is a Bitcoin UTXO?
Answer: An unspent transaction output that represents a discrete amount of bitcoin that can be used as input in a future transaction
UTXOs (Unspent Transaction Outputs) are the fundamental accounting units of Bitcoin; spending bitcoin means consuming UTXOs as inputs and creating new UTXOs as outputs.
What does 'deterministic key generation' mean in the context of HD wallets (BIP32)?
Answer: A single master seed can deterministically derive a hierarchical tree of all private/public key pairs
BIP32 HD wallets use a master seed to deterministically derive unlimited child keys, allowing full wallet recovery from a single backup seed phrase.
Which of the following best describes a 51% attack on Bitcoin?
Answer: An attacker controlling more than half of the network's hash rate can reorganize recent blocks and double-spend
With majority hash power, an attacker can mine a longer secret chain, reorg the honest chain, and potentially reverse recent transactions for double spending.
What is the purpose of a Bitcoin transaction's 'locktime' field?
Answer: To specify the earliest block height or timestamp at which the transaction can be included in a block
The nLockTime field makes a transaction invalid before a certain block height or Unix timestamp, enabling time-locked payment constructs.
What is the difference between a hot wallet and a cold wallet in Bitcoin?
Answer: A hot wallet is connected to the internet while a cold wallet keeps private keys offline
Hot wallets are internet-connected and convenient for frequent transactions, while cold wallets keep private keys isolated from online threats for long-term storage.
What is the purpose of Bitcoin's 'mempool'?
Answer: A holding area where unconfirmed transactions wait until miners select and include them in a block
The mempool (memory pool) is each node's local set of valid, unconfirmed transactions that miners draw from when constructing new blocks.