The Korea Customs Service has revealed a report where unlawful foreign exchange transactions made using virtual currency added up to a whopping $4 billion last year alone. The report highlights the potential risks associated with cryptocurrency, including its lack of regulation and vulnerability to fraudulent activity. However, it is worth noting that this figure only represents a small portion of the overall cryptocurrency market, which is estimated to be worth over $1 trillion. Nonetheless, authorities are urging caution and transparency in the use of digital currencies to avoid the risk of fraudulent and illicit activity.