By the end, you’ll be able to…
- Explain a privacy cost of combining inputs.
- Compare fee efficiency with data minimization.
Three questions to carry into this lesson.
Inputs tell a story
When a wallet combines outputs from different sources in one transaction, observers may infer relationships among them. Such heuristics are not perfect, but they can reveal more than a user intended. Address reuse, published receipts and third-party balance queries can add further links. Privacy is a system property involving both chain data and surrounding information.
Coin control exposes a choice
Some wallets let an operator choose which outputs to spend. That can support accounting separation or privacy goals, but introduces decisions about fees, change and operational complexity. Avoid universal rules such as always consolidate or never combine. The right analysis begins with the purpose, threat model and constraints of a specific situation.
Keep accounting separate from unnecessary publication
A community can preserve internal source-of-funds records without publishing every donor-to-expense relationship. A researcher should receive the minimum data needed for reconciliation. Exporting an xpub to a convenient service can expose a much wider history than one address lookup. This lesson does not provide a privacy guarantee or ask you to reorganize real funds; use labeled fictional outputs to reason about what a transaction reveals.
Practice on paper
A mock wallet has one output publicly tied to a fundraiser and one from a private artist sale. What new inference might arise if they are spent together?
I’ve tried it — show the worked answer
An observer may associate the sources with a common spending controller. The inference is not absolute proof of identity, but the transaction can reduce separation between previously distinct contexts.
Want to explore with buttons and instant feedback? Try the practice lab ↗
Make a choice. Discover why.
Choose an answer and check the explanation. You can retry as often as you like. These are practice questions, not a test of mastery; answers are not saved or sent.
One idea to take with you
Evaluate what construction and disclosure reveal together.
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