风险管控没做好。BitCoin

Is brilliant idea technically,  but very vulnerable politically.  It eats into government's lunch, no government will tolerate it.

The main reason ButCoin spiked so high is because smart money was trying to circumvent chinese capital control, so chinese government shut it down. And then US and all western governments put it under microscope for tax evasion.

And also all so called digital currency is based on current asymmetric encryption algorithms, especially RSA, so they all expose to future technology advancing risk, mainly quantum computing. 

Risk management is vitally important in capital market.  You should only allocate the amount of capital in one group of asset that you can afford to lose, and you always need an exist strategy before you deploy your capital.  Otherwise is not investing,  it's gambling . Gambling has Consequences,  sometimes can be fatal if one cannot handle it...

May professor zhang rest in peace,  such a brilliant mind in physics and science.