Ukraine has recently introduced currency control: when you exchange currency at Ukrainian exchange offices (banks), you now have to show ID.
Neither the Ukrainian nor the Russian Wikipedia says what I think is the main thing about currency control:
Countries with foreign exchange controls are also known as “Article 14 countries,” after the provision in the International Monetary Fund agreement allowing exchange controls for transitional economies. Such controls used to be common in most countries, particularly poorer ones, until the 1990s when free trade and globalization started a trend towards economic liberalization. Today, countries which still impose exchange controls are the exception rather than the rule.
Countries introduce currency control when they aren’t sure they can keep their balance of payments in proper shape. Here, I think, there’s another interesting goal as well. Currency control in the form just introduced here lets government bodies “unofficially” get information about citizens’ currency transactions and take the appropriate measures.
How do you protect yourself? You can’t. The newspaper Chastny Predprinimatel (“Private Entrepreneur”) recommends a few measures you can take:
After the bank staff make copies of your passport, ask them for those copies and write on them that the copies were made during a currency exchange, contain confidential information and must not be distributed or passed on to third parties. Sign them and add your full name.
“New currency exchange rules: how to protect your personal data”
[The paper’s legal source adds that this gives you some protection against your personal data being spread for illegal purposes.]