Tokyo-based bitcoin exchange Mt. Gox on Tuesday abruptly stopped trading, putting a question mark on the future of the digital currency that has been struggling to gain legitimacy.

Bitcoin is a form of digital currency that relies on a network of computers which solve complex mathematical problems as part of a procedure which verifies and records the details of each & every bitcoin transaction made. Its value depends on consumers' trust in it. There is no central authority for governing the supply of bitcoins.

Japanese authorities have launched a probe into the abrupt closure of Mt. Gox, which was once the world's biggest exchange for the virtual currency.

When asked about the abrupt shutdown of the Tokyo-based exchange, Chief Cabinet Secretary Yoshihide Suga said, "At this stage the relevant financial authorities, the police, the Finance Ministry and others are gathering information on the case."

Earlier this month, Mt. Gox had halted withdrawals after it detected unusual activity. The crisis erupted after more than 744,000 bitcoins reportedly missed because of malleability-related theft.

Nearly 12.4 million bitcoins, worth $6.2 billion at current prices, have been minted since the digital currency started circulating in 2009. But, the crisis at Mt. Gox has proved that the unregulated virtual currency is still far from ready for widespread use.