Safety Academy · Story 04 · Dust & privacy

Small change. Long shadow.

An unexpected Bitcoin payment is tiny. The privacy question is bigger.

Estimated 4 min read

DUST & PRIVACY6 scenes

A tiny Bitcoin payment arrives uninvited.

Ken opens his Bitcoin wallet to organise a payment. An unfamiliar incoming payment contains 700 satoshis. A satoshi is a hundred-millionth of a bitcoin. He was not expecting it.

Ken

“A stranger sent me 700 sats. Am I hacked?”

Illustration: A tiny Bitcoin payment arrives uninvited.

A satoshi is a small unit of bitcoin. Receiving it alone does not give anyone control.

Someone wants to see which coins travel together.

The scammer is not unlocking Ken’s wallet with a tiny payment. He is watching public transactions, hoping the small output later gets spent together with other outputs and creates useful links.

The Scammer

“Small payment. Interesting connections.”

Illustration: Someone wants to see which coins travel together.

In this Bitcoin example, the risk is exposing connections between addresses.

“Combine everything” includes the mystery payment.

Ken opens the payment preview. It lists which earlier payments, the transaction’s inputs, it will spend together. The unfamiliar 700 satoshis are included alongside his other coins. He pauses before confirming.

Ken

“I was only tidying up.”

Illustration: “Combine everything” includes the mystery payment.

Combining inputs can reveal links. Check which coins a transaction uses.

Captain separates theft from tracking.

Captain lays out the input list. Combining outputs can give an observer clues about common ownership. Receiving a small payment alone does not hand over keys, and not every small payment is an attack.

Captain Obvious

“Dust is not a remote control.”

Illustration: Captain separates theft from tracking.

A small receipt is a clue, not proof of a compromise.

Ken leaves the unexpected coins out.

Using his wallet’s documented coin controls, Ken excludes the unfamiliar output from this payment. He follows official guidance instead of paying a stranger to “clean” his wallet.

Ken

“You can keep your breadcrumb.”

Illustration: Ken leaves the unexpected coins out.

Use your wallet’s official coin-control guidance. Do not pay or sign for a dust-removal service.

He avoids creating that new link.

The unfamiliar output stays unspent in this example. Ken understands the privacy trade-off. The scammer’s notebook is less useful, although other public activity may still reveal links.

Ken

“My housekeeping does not need an audience.”

Illustration: He avoids creating that new link.

The habit: understand unexpected dust before consolidating it with your other coins.

The useful bit

An unexpected tiny payment is not a reason to panic or pay for a cleanup.

A tiny payment you did not expect is a tag, not a theft. Nobody can spend your coins because they sent you some.
Use your wallet's coin control and leave the unexpected coins out when you pay.
Never pay a 'dust removal' service and never type your recovery words to fix it.

I already did this

If you already spent the unfamiliar coins together with others, the public link cannot be erased. Review future coin selection using Trezor’s guide. Receiving dust alone does not justify moving everything or sharing recovery words.

Sources & further reading

Trezor: dusting and privacy ↗