Mystery shopper payments - Revision history

Belcher: /* Bad privacy example - Receiving donations spied on with mystery shopper payments */ Typo

2021-06-08T16:11:05Z

Bad privacy example - Receiving donations spied on with mystery shopper payments: Typo

← Older revision		Revision as of 16:11, 8 June 2021
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	# You set up a web server to give out unique addresses for each visitor.		# You set up a web server to give out unique addresses for each visitor.
	# An adversary who wants to get an idea of your total donation income donates a small amount of bitcoin to you.		# An adversary who wants to get an idea of your total donation income donates a small amount of bitcoin to you.
	# You combine all donations to use as inputs one transaction, thereby linking them together with the [[common-input-ownership heuristic]].		# You combine all donations to use as inputs in one transaction, thereby linking them all together with the [[common-input-ownership heuristic]].
	# The adversary now has a good idea of your total donation income.		# The adversary now has a good idea of your total donation income.

Belcher: /* See also */ Add link

2020-03-11T23:47:02Z

Belcher: Create page

2020-02-01T21:38:08Z

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Mystery shopper payments are a class of [[privacy]] attack. A mystery shopper payment is when an adversary pays bitcoin to a target in order to obtain privacy-relevant information.

For example, if the target is an online merchant then the adversary could buy a small item from the store. On the payment interface they would be shown one of the merchant's bitcoin [[address]]es. The adversary now knows that this [[address]] belongs to the merchant and by watching the blockchain for later [[transaction]]s other information would be revealed, which when combined with other techniques could reveal a lot of data about the merchant such as income, turnover, etc. This works because anybody on the entire internet can request one of the merchant's [[address]]es.

Mystery shopper payments are usually used as a starting point and then combined with other privacy attack techniques such as the [[common-input-ownership heuristic]] and change address detection. They work even if [[address reuse]] is avoided.

Mystery shopper payments can be resisted by awareness of what information is leaked. Care must be taken when spending incoming funds.

=== Bad privacy example - Receiving donations spied on with [[#Mystery_shopper_payment|mystery shopper payments]] ===
# You want to [[Receiving donations with bitcoin|accept bitcoin donations]] but don't want to reveal the total donated amount.
# You set up a web server to give out unique addresses for each visitor.
# An adversary who wants to get an idea of your total donation income donates a small amount of bitcoin to you.
# You combine all donations to use as inputs one transaction, thereby linking them together with the [[common-input-ownership heuristic]].
# The adversary now has a good idea of your total donation income.

Be mindful of what is being revealed with the [[common-input-ownership heuristic]].

== See also ==

* [[Privacy]]

[[Category:Privacy]]

← Older revision		Revision as of 23:47, 11 March 2020
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	* [[Privacy]]		* [[Privacy]]
			* [[Receiving donations with bitcoin]]

	[[Category:Privacy]]		[[Category:Privacy]]