CBP Bitcoin Privacy and Anonymity Techniques 2

Question 1

What is PayJoin (P2EP) in Bitcoin?

Accepted Answer

A technique where the recipient also contributes an input, breaking the common input ownership heuristic

Answer

In PayJoin, the recipient adds their own UTXO as an input, which breaks the assumption that all inputs belong to a single sender, confusing blockchain analysts.

Question 2

What is the Dandelion protocol (BIP156) designed to do?

Accepted Answer

Propagate transactions through a random path of nodes before broad broadcast, obscuring the originating node

Answer

Dandelion propagates transactions in a 'stem' phase through a few nodes before 'fluff' (normal broadcast), making it significantly harder to identify the originating node.

Question 3

What is coin control in a Bitcoin wallet?

Accepted Answer

The ability to manually select which UTXOs are used as inputs in a transaction

Answer

Coin control lets users choose specific UTXOs as inputs, avoiding automatic merging of UTXOs from different sources that could reveal wallet history to observers.

Question 4

How does Taproot (BIP341/342) improve Bitcoin privacy?

Accepted Answer

It makes complex multi-signature and smart contract spending conditions look identical to simple single-key transactions on-chain

Answer

Taproot uses Schnorr signatures and MAST so that multisig and complex scripts appear as single-key spends when cooperatively satisfied, hiding internal contract details.

Question 5

Why is a change output a privacy concern in Bitcoin transactions?

Accepted Answer

It creates a linkable output returned to the sender that reveals their wallet address for future analysis

Answer

A change output returns unspent funds to the sender's wallet, and blockchain analysts can often identify it, linking it to the sender and their future transactions.

(CBP) Certified Bitcoin Professional Practice Test

(CBP) Certified Bitcoin Professional Practice Test

CBP Bitcoin Privacy and Anonymity Techniques 2