One of the key principles of the blockchain is "decentralization". This makes it a more secure system than a centralized system with all the rights. **However, almost 1/3 of the blockchains and virtual currencies are held by the centralized exchanges.**

Almost all of the richest wallet is owned by the cold wallet of large exchanges.

**It is a big irony that most of the blockchains with decentralization as core values are committed to centralized exchanges.** Of course, because trading is one of the most important parts, it is also an unavoidable phenomenon.

However, exchanges are exposed to a variety of risks that may arise from hacking and insider cheating. In the case of POW coins, issuance rights, decisions and ownership are separated, so even if a hacker hackers a large amount of coins on the exchange, only the ownership is stolen. **However, if issuance rights, ownership rights, and decision rights are determined by stake(POS and DOPS), a hacker can have a large influence on the entire blockchain if a hacker hacked a large number of coins.** As the number of DPOS based coin increase, when a centralized exchange is hacked, the damage suffered by blockchain users will be greater.

A decentralized exchange is necessary to prevent this from occurring. In the meantime, various attempts have been made to create a decentralized exchange. But they all have a fatal disadvantage of **"slow trading speed".** Even the fastest decentralized exchange offered by Bitshare has a delay of three seconds.

**For a decentralized exchange to succeed, it must basically provide the same level of trading speed as a centralized exchange.** If you can not solve this problem, no decentralized exchange can succeed.

Many teams are currently challenging this issue. And if one of them succeeds, the word "exchange hacking" will disappear into history. It will also enable secure cryptocurrency trading and storage based on blockchain.