Before talking about the characteristics of bitcoin with others, my friend raised doubts that when trading on the trading platform, we should save the bitcoin to the address specified by the platform, that is to say, we handed the bitcoin to the trading platform in exchange for " At any time to the platform to mention the credit "commitment. But there have been several incidents in which platforms were stolen and bitcoin stolen, investors suffered. Moreover, due to the characteristics of bitcoin, the stolen currency has no traceability, that is to say it does not even know whether it is a trading platform to defend itself from theft. Is it ironic that a so-called decentralized currency relies heavily on the credit of the trading platform? This makes me feel embarrassed, I do not know how to accurately refute him, I hope you can express your opinion.