Bitcoins. (Flickr)

This is a heavy setback for Bitcoin, a new virtual currency just gaining traction and legitimacy after being accepted by companies as famous as Elon Musk's Tesla and being recognized by the U.S. Congress.

Tokyo-based Mt. Gox, the world's foremost Bitcoin exchange, lost 744,408 Bitcoins after hackers exploited a bug in Bitcoin's wallet software.

A leaked document apparently from within Mt. Gox labeled "Crisis Strategy Draft" explained "744,408 BTC are missing due to malleability-related theft which went unnoticed for several years."

Wired.com reports the faceless hackers have been hacking under Mt. Gox's radar for over two years.

Immediately after the online theft, various Bitcoin businesses - i.e. Coinbase - have published statements defending the legitimacy of Bitcoin.

"This tragic violation of the trust of users of Mt. Gox was the result of one company's abhorrent actions and does not reflect the resilience or value of bitcoin and the digital currency industry," reads the document. 

In spite of their support for Bitcoin, even the regulators of what was just the largest Bitcoin establishment in the world don't see a future for the virtual currency after the heavy loss.

"This could be the end of Bitcoin, at least for most of the public," reads the Crisis Strategy Draft.

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