Photo by Yuriko Nagao/Getty ImagesA hacker responsible for a $610 million cryptocurrency theft has already returned $342 million.The hacker, nicknamed "Mr. White Hat", said that they did the heist on Poly Network "for fun."There are still $268 millions of ether left that have not been returned.Subscribe to our daily newsletter 10 Things Before The Opening Bell.As hacker "Mr. White Hat," continues to return stolen assets to Poly Network, one of the largest cryptocurrency heists in history is slowly being reversed.Poly Network, a peer to peer DeFi platform, stated Wednesday that $610 million was stolen from its platform due to a flaw in its code. The hacker returned $258 million within hours of the attack.Based on tweets from Poly Network, Mr. White Hat continues to return the money. Poly Network has received $342 million in total, while $268 million of ether remains.This heist highlights the risks associated with cryptocurrencies and decentralized financial platforms. These platforms allow users to transact without traditional protections from exchanges or banks."All remaining Ethereum user assets (except the USDT frozen) were transferred to the multisig wallet managed by Mr. White Hat, and the Poly Network team. The repayment process is still not complete. We hope to keep in touch with Mr. White Hat to ensure safe recovery of user assets and provide accurate information to the public," Poly Network stated in a Thursday tweet.In a Q&A embedded in a digital currency transaction, the hacker behind the heist stated that he did the hack "for fun.""When I saw the bug, my feelings were mixed. You have to ask yourself, what would you do if you were facing such a lot of fortune? I can't trust anyone! I cannot think of a solution other than to save it in a trusted account and keep myself anonymous and secure," Mr. White Hat stated. He also said that they are returning the stolen assets because "I don't care about money!"Read more Grayscale has appointed Fundstrat's David Grider to its new head for research. This crypto expert shared his reasons for making the move and what has been driving the soaring prices of crypto assets, as the market turns risky again.