Cryptocurrency traders around the world could face more limitations when it comes to trading their favourite digital asset. Regulators in Japan will launch more on-site investigations for several cryptocurrency exchange operators this week, saying some of them are potentially vulnerable to cyber attacks. They have ordered a surprise check to Coincheck last Friday, after the Tokyo-based operator had 530 million U.S. dollars in digital money stolen by hackers in late January. The regulator said, it will investigate another 31 cryptocurrency exchanges in Japan for security gaps, and they have to submit reports on their system risk management and storage of cryptocurrencies.