As bitcoin and crypto currencies continue to grow, they become desirable targets for hackers, which forced a relatively unknown South Korean exchanger with crypto-currencies, Youbit, to file a bankruptcy petition.

This is the second time that hackers managed to get access to the user's funds on Youbit (not to be confused with Yobit), removing about 4,000 bitocons in April (when it was known as Yapizon).

Hacking occurred today, at 4:35 am, the attackers managed to get a 17% stake in the stock exchange.

In their official statement, they apologized for the lost funds and announced that all trades had been stopped.

Meanwhile, it is reported that the Korean Internet Security Agency (KISA) will investigate the attack.

Despite the fact that crypto-currencies are quite stable, protected by complex cryptographic algorithms, their safe storage is quite another matter.

Like paper money or physical assets, such as gold, crypto-currencies are stored in purses, which can only be accessed through a special pair of public and private keys. Anyone who has access to a secret wallet key can remove and move all funds, and even if such thefts can be tracked on a block chain, after losing them they can not be recovered because of the immutable nature of the technology.

One of the most famous (and the biggest bug-kills thefts) was the Gox scandal, which, once lost more than 744,000 bitokoynov, (14 billion dollars in current prices)

Given all this, it can not be stressed that the presence of crypto currency on exchanges is extremely risky, especially for those who use stock exchanges for storage. It is strongly recommended that you transfer the crypt to a secure dedicated purse whose personal keys are under your control.