Certified Bitcoin Professional (CBP) — Questions and Answers

Question 1: What term describes the gradual decrease in purchasing power of a currency over time?

Devaluation
Stagflation
Deflation
Inflation (Correct answer)

Correct answer: Inflation

Inflation is the rate at which the general level of prices rises, eroding the purchasing power of money over time.

Question 2: What is a 'keysend' payment in Lightning?

A spontaneous Lightning payment without a pre-generated invoice (Correct answer)
A Bitcoin transaction signed by multiple keys
A method to recover lost wallet funds
A payment that sends private keys to another node

Correct answer: A spontaneous Lightning payment without a pre-generated invoice

Keysend allows sending a Lightning payment to a node's public key without the recipient needing to generate an invoice first.

Question 3: What is a 'dust attack' in the context of Bitcoin privacy?

A mining pool technique that exploits small block reward variations
Sending tiny Bitcoin amounts to target addresses so that when the dust is spent with other UTXOs, the owner's addresses become linked (Correct answer)
A spam attack that floods the mempool with thousands of low-fee transactions
A method of obscuring transaction amounts by appending random small values

Correct answer: Sending tiny Bitcoin amounts to target addresses so that when the dust is spent with other UTXOs, the owner's addresses become linked

Attackers send tiny 'dust' outputs to target addresses; when the victim later spends them alongside other UTXOs, the attacker can link those UTXOs and deanonymize the wallet.

Question 4: What is the primary regulatory objective for imposing Know Your Customer (KYC) and Anti-Money Laundering (AML) requirements on cryptocurrency exchanges?

To prevent the use of cryptocurrencies for illicit activities such as money laundering and terrorist financing. (Correct answer)
To guarantee that all exchange users have the technical expertise to manage their own private keys securely.
To protect investors from price volatility by ensuring they meet certain income requirements.
To build a government database of all cryptocurrency holders for the purpose of future wealth taxes.

Correct answer: To prevent the use of cryptocurrencies for illicit activities such as money laundering and terrorist financing.

The core purpose of KYC and AML regulations is to prevent financial systems from being used for illegal purposes. By requiring exchanges to verify the identity of their customers (KYC), regulators aim to make it more difficult for criminals to launder money, finance terrorism, or engage in other financial crimes. This allows for the monitoring and reporting of suspicious activity (AML).

Question 5: What is the generator point G in Bitcoin's elliptic curve cryptography?

The coordinate origin (0,0) of the secp256k1 elliptic curve
The highest-value point on the curve representing the maximum private key value
A predefined point on the secp256k1 curve used as the base for scalar multiplication to derive public keys (Correct answer)
A random point generated fresh for each Bitcoin key pair creation

Correct answer: A predefined point on the secp256k1 curve used as the base for scalar multiplication to derive public keys

G is a standard, publicly known base point on secp256k1; a public key is computed as k×G where k is the private key scalar.

Question 6: In Bitcoin's Merkle tree, what is the Merkle root used for?

To generate new Bitcoin addresses for miners as a reward
To summarize all transactions in a block into a single hash for efficient verification (Correct answer)
To encrypt the block header before broadcasting to the network
To store the private keys of all transaction senders in a block

Correct answer: To summarize all transactions in a block into a single hash for efficient verification

The Merkle root is a single hash representing all transactions in a block, enabling lightweight clients to verify transactions without downloading the full block.

Question 7: In economics, what is the 'double coincidence of wants' problem associated with barter systems?

Both parties must want the same quantity of goods
Both buyers must arrive at the market at the same time
Two currencies must be accepted by both trading parties
Each party must have exactly what the other wants simultaneously (Correct answer)

Correct answer: Each party must have exactly what the other wants simultaneously

The double coincidence of wants means barter only works when each party has what the other wants at the same time, making trade very difficult.

Question 8: What is a UTXO in Bitcoin?

Universal Token eXchange Order
Unspent Transaction Output (Correct answer)
Unverified Transaction eXchange Output
Unsigned Transaction eXchange Operation

Correct answer: Unspent Transaction Output

A UTXO (Unspent Transaction Output) is the output of a Bitcoin transaction that has not yet been used as an input in another transaction.

Question 9: When analyzing a proposed hard fork, which factor most directly determines whether two chains will survive long-term?

Whether each chain has sufficient economic activity and hash rate to sustain itself (Correct answer)
Whether the fork was announced more than one year in advance
The number of BIPs referenced in the proposal
The programming language used to implement the change

Correct answer: Whether each chain has sufficient economic activity and hash rate to sustain itself

Long-term chain survival depends on sustained economic value attracting miners and users; without both, a chain collapses.

Question 10: What is the purpose of the 'locktime' field in a Bitcoin transaction?

Sets the expiry time for unconfirmed transactions
Encrypts the transaction data
Specifies the earliest block height or timestamp at which the transaction can be included (Correct answer)
Determines how long miners must wait before claiming fees

Correct answer: Specifies the earliest block height or timestamp at which the transaction can be included

Locktime specifies the earliest block height or Unix timestamp before which the transaction cannot be mined into a block.

Question 11: In Bitcoin, what is 'fee bumping' via Child-Pays-For-Parent (CPFP)?

Paying miners extra to process transactions in reverse order
Adding signatures to increase a transaction's priority score
Creating a child transaction that spends an unconfirmed parent's output with a high fee, incentivizing miners to confirm both transactions together (Correct answer)
Splitting a large transaction into smaller ones to reduce per-byte fees

Correct answer: Creating a child transaction that spends an unconfirmed parent's output with a high fee, incentivizing miners to confirm both transactions together

CPFP works because miners evaluate the combined fee rate of a parent-child pair, motivating them to mine the low-fee parent to claim the high-fee child's reward.

Question 12: A user wants to pay for coffee using Bitcoin without waiting for block confirmation. Which solution is most appropriate?

Multi-signature Bitcoin transaction
Lightning Network payment channel (Correct answer)
On-chain Bitcoin transaction with 1 confirmation
Bitcoin paper wallet transfer

Correct answer: Lightning Network payment channel

Lightning Network payments settle instantly off-chain, making them ideal for small, time-sensitive purchases like coffee.

Question 13: What was the primary problem with early paper money (banknotes) issued by private banks in the 1800s?

Different banks issued notes that varied in trustworthiness and redemption reliability (Correct answer)
The government taxed paper money at higher rates than coins
Paper was too fragile to use as currency
Paper notes could not be divided into smaller amounts

Correct answer: Different banks issued notes that varied in trustworthiness and redemption reliability

Private bank notes had varying reliability since each bank's notes were only as good as that bank's reputation and gold reserves, creating confusion and risk.

Question 14: What does it mean when economists say money should be 'scarce'?

Money should be difficult to carry
Currency must be made from rare materials only
The supply of money must be limited to maintain its value (Correct answer)
Money should only be available to wealthy individuals

Correct answer: The supply of money must be limited to maintain its value

Scarcity ensures money maintains value; if money were infinitely available, it would lose purchasing power and cease to function effectively.

Question 15: What is the 'gap limit' in HD wallet address discovery?

The number of consecutive unused addresses a wallet scans before stopping address discovery (Correct answer)
The maximum derivation depth allowed by BIP-32
The maximum number of UTXOs a wallet can manage
The block confirmation threshold before funds are considered received

Correct answer: The number of consecutive unused addresses a wallet scans before stopping address discovery

Wallets stop scanning for transactions after finding a configurable number (typically 20) of consecutive unused derived addresses, balancing thoroughness with performance.

Question 16: What is key stretching in the context of Bitcoin wallet encryption?

Deriving multiple child keys from one parent
Using a slow hash function to make brute-force attacks computationally expensive (Correct answer)
Increasing the bit length of private keys
Splitting a key across multiple backups

Correct answer: Using a slow hash function to make brute-force attacks computationally expensive

Key stretching applies algorithms like PBKDF2 or bcrypt to a password, deliberately increasing computation time to deter brute-force attacks.

Question 17: Which characteristic of a cryptographic hash function is most critical for ensuring the immutability of the Bitcoin blockchain?

Fast computation
Fixed-size output
Collision resistance
Pre-image resistance (Correct answer)

Correct answer: Pre-image resistance

Pre-image resistance means it is computationally infeasible to find an input that hashes to a specific output. For the blockchain, this means it's practically impossible to alter a block's data without changing its hash. Since each block's hash is included in the subsequent block, changing a historical block would require re-mining that block and all subsequent blocks, which is computationally infeasible. This property directly contributes to the blockchain's immutability.

Question 18: Why is it computationally infeasible to reverse a transaction buried under many Bitcoin confirmations?

An attacker would need to redo all the proof-of-work for each subsequent block while outpacing the honest network (Correct answer)
Node operators vote to reject any chain reorganization deeper than 6 blocks
The Bitcoin protocol locks transactions permanently after 6 blocks
Bitcoin uses quantum-resistant encryption that prevents hash reversals

Correct answer: An attacker would need to redo all the proof-of-work for each subsequent block while outpacing the honest network

Reversing a deeply confirmed transaction requires re-mining all blocks from that point forward faster than the honest network adds new blocks.

Question 19: What is 'fiat money'?

Currency that has value because a government declares it legal tender (Correct answer)
Money issued by private banks
Currency backed by a physical commodity like gold
Cryptocurrency backed by stablecoins

Correct answer: Currency that has value because a government declares it legal tender

Fiat money derives its value from government decree rather than intrinsic value or backing by a physical commodity.

Question 20: What improvement does Taproot bring to Bitcoin transactions?

Improved privacy and efficiency by making complex scripts look like simple payments (Correct answer)
Faster mining of new blocks
Elimination of transaction fees
Increased block size limit

Correct answer: Improved privacy and efficiency by making complex scripts look like simple payments

Taproot uses Schnorr signatures and MAST to make complex multi-sig and smart contract transactions indistinguishable from simple payments, enhancing privacy and reducing fees.

Question 21: What is a 'coinbase transaction' in Bitcoin?

A transaction originating from the Coinbase exchange
The first transaction in each block that creates new bitcoin and collects fees for the miner (Correct answer)
The transaction that funds a Lightning Network channel
A transaction that consolidates many UTXOs into one output

Correct answer: The first transaction in each block that creates new bitcoin and collects fees for the miner

The coinbase transaction is the mandatory first transaction in every Bitcoin block, through which miners receive the block subsidy plus transaction fees.

Question 22: In asymmetric cryptography (also known as public-key cryptography), which key is kept secret and which is shared?

The public key is kept secret, and the private key is shared.
Both the public and private keys are shared.
The private key is kept secret, and the public key is shared. (Correct answer)
Both the public and private keys are kept secret.

Correct answer: The private key is kept secret, and the public key is shared.

The core principle of asymmetric cryptography is the use of a key pair: a private key, which must be kept secret by the owner, and a public key, which can be freely distributed. Data encrypted with the public key can only be decrypted by the corresponding private key, and a signature created with the private key can be verified with the public key.

Question 23: What routing privacy protocol does the Lightning Network use?

Ring signatures
Zero-knowledge proofs
Onion routing similar to Tor (Correct answer)
Merkle trees

Correct answer: Onion routing similar to Tor

Lightning uses onion routing to wrap payment instructions in layers of encryption so each node only knows the previous and next hop, not the full path.

Question 24: What is the significance of the 'extraNonce' field used by miners?

It extends the nonce search space within the coinbase transaction (Correct answer)
It records the pool's fee percentage
It stores the miner's wallet address
It encodes the software version used

Correct answer: It extends the nonce search space within the coinbase transaction

Since the 32-bit nonce space exhausts quickly, miners use the extraNonce in the coinbase to expand their search space.

Question 25: What distinguishes a custodial wallet from a non-custodial wallet?

Custodial wallets support hardware security modules; non-custodial do not
Non-custodial wallets require KYC; custodial wallets do not
Custodial wallets use HD derivation; non-custodial use random key generation
In custodial wallets a third party holds the private keys; in non-custodial wallets the user controls their own keys (Correct answer)

Correct answer: In custodial wallets a third party holds the private keys; in non-custodial wallets the user controls their own keys

Custodial wallets delegate key control to a service provider, meaning users trust the provider's security; non-custodial wallets give users sole control of their private keys.

Question 26: In the context of SegWit2x (2017), why did the hard fork portion ultimately fail to activate?

Miners refused to signal because the block reward would have been halved
The code contained a critical security vulnerability discovered at the last minute
The US government issued a ruling preventing its activation
Key signatories withdrew support and the fork lacked sufficient node and economic backing (Correct answer)

Correct answer: Key signatories withdrew support and the fork lacked sufficient node and economic backing

Major SegWit2x backers publicly withdrew weeks before the planned November 2017 activation, collapsing support for the 2MB block hard fork.

Question 27: How does the Bitcoin network calculate the next difficulty target?

By polling miners for their reported hashrate
By comparing the time to mine the last 2,016 blocks against 20,160 minutes (Correct answer)
By using a predictive algorithm based on mempool congestion
By averaging the last 10 block times

Correct answer: By comparing the time to mine the last 2,016 blocks against 20,160 minutes

Every 2,016 blocks, the protocol compares actual elapsed time to the 20,160-minute ideal and adjusts difficulty proportionally (capped at a 4x change).

Question 28: What is the purpose of 'checkpoints' historically used in Bitcoin Core?

To hardcode known-good block hashes to protect against certain history-rewriting attacks (Correct answer)
To pause the blockchain for scheduled maintenance
To mark blocks where difficulty adjustments occurred
To identify blocks mined by Satoshi Nakamoto

Correct answer: To hardcode known-good block hashes to protect against certain history-rewriting attacks

Checkpoints in early Bitcoin Core hardcoded hashes of key historical blocks to prevent attackers from forking the chain before those points.

Question 29: How does Bitcoin affect traditional banking systems?

It eliminates the need for international trade regulations
It reduces reliance on traditional banks by enabling direct transactions (Correct answer)
It requires banks to hold Bitcoin reserves
It increases the demand for cash transactions

Correct answer: It reduces reliance on traditional banks by enabling direct transactions

Bitcoin provides an alternative to traditional banking by enabling peer-to-peer transactions without intermediaries.

Question 30: What is the 'difficulty adjustment' in Bitcoin and how often does it occur?

An adjustment triggered whenever hash rate drops by 20%
A change in difficulty that happens with every new block
An automatic recalibration of mining difficulty every 2016 blocks (~2 weeks) to target 10-minute block intervals (Correct answer)
A manual update by core developers every month to control inflation

Correct 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.

Certified Bitcoin Professional (CBP)

The CBP certification, issued by the CryptoCurrency Certification Consortium (C4), validates professional working knowledge across 33 Bitcoin topics spanning six domains including cryptography, mining, wallets, and the Bitcoin protocol.

Questions

8 min

Time Limit

70%

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