One of the chief strengths of digital currencies is becoming their weakness.

Freedom from regulation was the big draw of Bitcoin, Ether and their counterparts. But the exchanges set up to trade them often lack basic controls over identity, fraud, technology and even trading volume, a Reuters investigation shows.

Without fixes, such weaknesses will consign those currencies to the financial fringe.

These markets can be vulnerable to hacking. For instance, the exchange Kraken suffered a denial-of-service network interruption in May, during which the price of ether on its platform dropped 70 percent. Such reactions can be intensified by a lack of circuit breakers that halt trading.

Virtual heists are common, too, according to the Reuters special report. About 980,000 Bitcoins have been stolen in at least 36 incidents since 2011. At current rates, that’s worth $4 billion.

Some exchanges also fail to demand the most basic security checks and know-your-client procedures that more traditional venues insist on. The Poloniex exchange asked some users to supply only a name, email address and country of operation. And some Chinese exchanges have inflated deal flow to attract business, according to former employees.