One of the most common fear of all bitcoin-lovers is losing the private key or being hacked. The question of safety becomes more and more important every day, in proportion to bitcoin’s growth.

Up to 50% of all mined bitcoin was lost during the years, with a value of $20 bln. Obviously, some people see this like a chance to make some money.

Sun Zeyu, 27 developed an offline physical wallet named Coldlar that stores users’ bitcoins and can be accessed by scanning a QR code. Bitcoin security is an important and difficult question, so the circumvention of online wallets means a better control over the money. His business thrives.

He started to work over bitcoin after attending the Huobi’s seminar at the university. Now money comes to him from both his startup and the trading activity, and “it’s hundreds or thousands times more than the 10,000 yuan per month” he was earning when he first dabbled in bitcoin three years ago.

Sun predicts that in 10 years one bitcoin will be the equivalent of one house in Beijing. The extreme volatility of bitcoin is “just like breathing,” he insists, and the profit will beat all the “bumps in the road.”