1. If the blockchain also has 3 15, then Ethereum must be on the list. Since the operation of Ethereum, there have been many major safety accidents caused by loopholes.

2.2065438+June 2006 17, the blockchain suffered a heavy blow in history. Due to the major defects in the smart contract of Ethereum, TheDAO, the largest crowdfunding project in the blockchain industry (the assets before the attack were about 654.38 billion US dollars), was attacked, resulting in more than 3 million Ethereum assets leaving TheDAO asset pool. On July 2 17, 2 1, the smart contract coding company even warned that its wallet software of 1.5 and later versions was defective. According to the data of Etherscan.io, it is confirmed that150,000 ethereum coins worth $30 million were stolen. 2017165438+18 October, there was another major bug in the cheap wallet, and several signature vulnerabilities were exploited by hackers, resulting in hundreds of millions of dollars of funds being frozen.

3. The open source software of Ethereum is mainly written by geeks in the community. At present, the known vulnerabilities include Solidity language vulnerability, short url vulnerability, transaction order dependence, timestamp dependence, reentry attack and so on. This vulnerability may be exploited when calling the contract, and the difficulty of updating the smart contract after deployment also makes the impact of this vulnerability more extensive and lasting.