From the evening of March 18th to March 19th, the community had a lot of discussions on the Filecoin "double-spending" incident. After confirming with the Filecoin official and other multi-party platforms: Filecoin does not have the "double-spending" problem, and the Filecoin chain is safe. "
What is "double flower"?
"Shuanghua" is actually a relatively unfamiliar term for most people.
"Double spending" is also known as double spending, which means double spending. It means that in the digital currency system, due to the reproducibility of data, the system may have the same digital asset being reused due to improper operation.
What does it mean?
First of all, double spending is only possible in the digital currency transaction system. When we use cash to trade, there is no double payment problem.
Because you transferred 5,000 yuan to me on WeChat, after I received it, your account will be 5,000 yuan less, and my account will be 5,000 yuan more. In other words, in cash transactions, the successful transaction of assets means real The transfer of assets was completed locally.
However, in the block chain in the world is not the same, because the transaction is digital assets that is actually passed between a number of virtual information, and as a transaction record record from generation to link to the block chain, there In a time window, what we call "double spending" actually makes use of the "time difference."
If you achieve a "double", the attack hit who can make flowers out of digital assets back on their own account.
This is like someone using a coin-operated phone and slyly wearing a string on the coin. Although the coin is thrown, the actual transaction is not completed. He can use the string to take out the coin after the phone call. If you do it in the same way, you can make countless calls with this coin.
Conflict transaction flow chart
Although "double spending" can make people earn double income, there are very few "double spending" events that have successfully occurred in the entire history of the blockchain.
In the Filecoin network, it has never happened!
The beginning and end of the Filecoin double spend event
3月18日晚，某用户在某数字资产平台内充入FIL，双花操作后再提现，依然可以再收到一笔同样数量的FIL，也就是说，用户某数字资产平台充值了61000个FIL，结果得到了120000个FIL。
这时，有用户认为是Filecoin网络发生了双花事件而导致的，但实际情况是，该数字资产平台自己记账记错了，也就是说，这并不是Filecoin链的问题！
不过，针对该事件，Lotus团队也进行了彻底调查，确定没有发现任何Filecoin网络和RPC API代码的相关问题，即链本身不存在双花问题，API代码也没有错误。
至于数字资产平台的交易记录，也已经在修正了，同时Filecoin官方团队也正在审查相关平台记账系统中的充值处理逻辑，以改正他们的API使用。
为什么会存在对“Filecoin 双花”的误解？
所谓的Filecoin“双花”事件，本就是一场闹剧。但是，为什么依旧有社区会对该事件产生误解，既然Filecoin链没有问题，API代码也没有错误，那么，问题又在哪里呢？
该问题的核心在于部分数字资产平台以及部分Filecoin区块链浏览器对于Lotus的链状态检查API使用不当，在处理多个类似消息时，其处理方式与所期待的不同。
而误解Lotus API的输出，就会导致记账系统将原始消息和替换消息都算作相同的发送者和接收者。
简单来说，就是人们对链的检查方式，这会呈现出消息被处理了两次的样子，进而产生了误解。
具体来说，就是部分数字资产平台使用了一种错误的处理链状态的方式——在tipset的每个块上调用ChainGetBlockMessages，然后在这些消息上调用StateGetReceipt。
When StateGetReceipt is called on two similar messages (one is executed and the other is skipped), it will provide the same result to the person, which will give people the illusion that both messages are executed .
Community, make Filecoin better and better
From the evening of March 18 to the early morning of March 19, since receiving feedback on the incident, the relevant Filecoin team immediately verified the relevant information, and timely updated the latest information on Twitter, slack, and official website blogs. Share and update.
First of all, it turns out that the Filecoin chain is not problematic and safe , and the "double spend" incident is just an oolong and farce!
Secondly, the Filecoin official team attaches great importance to the problems reported by the community. It is very worthy of recognition to solve problems in a timely manner when they encounter problems and assist the community in solving problems. This also proves that "Filecoin belongs to the community and belongs to us. People are the joint efforts of all of us to make the Filecoin network better and better." Finally, IPFS & Filecoin is in a booming and explosive era of big data. In this era, there are trillions of dollars for distributed storage technology. Each of our IPFS&Filecoin participants will take advantage of distributed storage. The east wind is flying in the sky. Investors who want to know more about IPFS and Filecoin, please contact the IPFS China Community Operations Officer ( WeChat ID: chuanzhang129 ).