Dust Attack

A dust attack is a privacy attack in which an adversary sends tiny amounts of bitcoin, often a few hundred satoshis, to a large number of addresses, then watches the blockchain to see where those crumbs move. If a victim's wallet later combines the dust with other coins in one transaction, the attacker can link addresses together and begin mapping the victim's holdings.

Why it matters

The attack exploits Bitcoin's transparency. Every transaction is public forever, and the most common heuristic in chain analysis assumes that all inputs to a transaction belong to the same owner. Dust turns that heuristic into a tracking beacon: the attacker plants a marked coin and waits for the victim's own wallet software to incriminate it by spending it alongside their other funds.

Defenses are straightforward. Modern wallets flag incoming dust and allow users to freeze specific UTXOs so they are never spent, and coin control features let careful users decide exactly which outputs move together. Receiving dust costs a victim nothing if it is simply left untouched.

In the gold vs bitcoin debate

Dust attacks illustrate a genuine gold advantage: physical metal produces no public record, so holding it leaks no information. Bitcoin's ledger is radically transparent, which aids auditability but demands active privacy hygiene from users. Advocates respond that transparency is a tradeoff, the same property that exposes users to dust attacks also lets anyone verify the entire money supply, something no gold vault can offer.