SEOUL -- The hacking and collapse of a South Korean cryptocurrency exchange this week has heightened suspicions that the North is targeting the virtual coins as a source of foreign currency, raising concerns over the security vulnerability of such exchanges.
Yapian, the operating company behind the exchange Youbit, posted an apology Tuesday informing users it was filing for bankruptcy protection. Around 4:35 a.m. that day, Yapian said, hackers broke into a Youbit "hot wallet" -- cryptocurrency storage kept constantly online and ready for exchange. The exchange lost about 17% of its assets.